Many organizations manage more than one email list, audience, or brand within the same ecosystem. Whether you're a university, a DTC company with sub-brands, or a nonprofit with regional chapters, chances are you have overlapping audiences and teams trying to manage separate lists. Unfortunately, most email tools are not built to handle that complexity cleanly.

This creates two common (and equally frustrating) scenarios:

1. Teams operate out of separate ESP workspaces, with no unified view of the subscriber.

2. Everyone works out of one shared workspace, constantly getting in each other's way.

At Scalero, we've seen this up close. One of our clients, Thinx, manages three separate brands: Thinx, Speax, and Thinx Teens. Customers might shop across all three, but marketing teams need separation. Navigating this in a single ESP is no small feat.

So who faces this challenge, what tools are best suited for it, and how can you build the visibility and control you need? Let's dive in.

Who faces this challenge

Here are the most common types of organizations that run into cross-list complexity:

• Universities

  • Alumni, donors, athletics fans, current students, faculty

• Consumer brands with sub-brands

  • For example, Gap Inc., which owns Old Navy, Banana Republic, Athleta, and Gap

• Media companies

  • Readers, event attendees, podcast listeners, subscribers

• Franchise or multi-location businesses

  • Individual owners, local marketing lists

• Hospital systems or clinics

  • Patients, donors, staff, event attendees

• Retailers or corporations with international divisions

  • Same customer across multiple regions

• Nonprofits with regional chapters

  • Local donors, volunteers, staff, event lists

In each case, people may appear in multiple lists, and teams may operate semi-independently. That creates risk for duplicate sends, conflicting messages, or data that never gets shared.

The workspace dilemma

It can be a dilemma deciding how to set up your ESP when you manage multiple sub-brands. Should each brand get its own workspace to stay organized, or should everything live under one roof to enable a unified customer view?

Option 1: Separate workspaces

• Pros: Keeps teams organized, avoids accidental sends

• Cons: Data becomes siloed; no single view of a person

Option 2: One shared workspace

• Pros: Unified customer view; shared lists and templates

• Cons: High risk of internal errors; no workspace boundaries

What ESPs work best for complex organizations?

Here are some platforms better suited for this challenge:

• Customer.io: Flexible and developer-friendly and has multi-workspace governance.

• Iterable: Great for multi-workspace setups with advanced identity modeling. Can support overlap if you architect carefully.

• Simon Data: Not an ESP, but a strong orchestration layer for brands using Snowflake. Handles complex data use cases.

• Salesforce Marketing Cloud: Built for enterprise complexity. Expensive but powerful if managed well.

• Klaviyo: Solid for Shopify-connected sub-brands. Limited visibility across accounts, but does offer multiple workspaces.

• Braze: Great segmentation in a single workspace.

• Bloomreach: Designed for ecommerce-first brands. It has strong segmentation and journey capabilities, and you can manage multiple sub-brands with careful planning.

How to get visibility across workspaces

To manage a single subscriber across multiple workspaces or brands, you need infrastructure and process. Here's how:

1. Establish a unique global contact ID

   • Use email or database ID consistently across systems

   • Ensure each ESP or workspace references this ID for all key events

2. Centralize data in a warehouse or CDP

   • Use platforms like Snowflake, BigQuery, Segment, or Hightouch

   • Bring in ESP event data, customer attributes, and engagement across brands

3. Use reverse ETL to enrich ESP workspaces

   • Push unified traits into each ESP (like "has_donated", "is_student", "attends_events")

   • Maintain consistent profile attributes to enable smarter segmentation

4. Build a contact visibility dashboard

   • Create a single dashboard using tools like Looker, Tableau, or Retool to show:

     • Where the user exists

     • Which emails they have received

     • Their engagement levels by workspace

5. Sync suppressions and preferences across systems

   • Make sure global unsubscribes or consent flags are honored everywhere

   • Use a preference center that updates each ESP via API or data warehouse

6. Standardize field names and lists

   • Align on naming conventions like brand_affiliation, donor_status, global_unsubscribed

   • Avoid each workspace inventing its own structure

7. Define internal governance rules

   • Decide who owns which data fields and audiences

   • Document processes for segmentation, campaign reviews, and send approvals

8. Use APIs or webhooks for real-time syncing

   • Set up cross-system alerts and updates when someone unsubscribes or makes a purchase

Best practices for managing overlapping audiences

• Appoint a central data or lifecycle owner

  • Someone should own the full-picture strategy and ensure systems talk to each other

• Set up clear roles and permissions

  • Limit who can send to shared audiences

  • Assign ESP access by team, brand, or function

• Maintain a shared marketing calendar

  • Avoid over-emailing shared contacts across teams or brands

  • Coordinate campaigns, launches, and holidays

• Audit campaigns for collision risks

  • Run overlap checks before launch to identify duplicate messages or unsubscribed users

• Use a preference center

  • Let users manage their own subscriptions across brands or topics

  • Reflect preferences instantly across all ESPs

• Centralize profile building and decentralize execution

  • Build and enrich profiles in one place like a data warehouse

  • Let each brand use that data independently, safely, and intelligently

Conclusion

Managing multiple brands or audiences within one ESP or across several does not have to feel like wrestling an octopus. With the right structure, data layer, and internal process, you can reduce errors, respect your audience's preferences, and make each message more relevant.