Hi @ScottCodes, welcome to the community!
Unfortunately, from what I can tell working with lots of Klaviyo multi-accounts, each Klaviyo account is separate from one another.
If you want avoid downloading/importing contacts from Account B into Account A, you may want to consider doing this programmatically via the Klaviyo API.
Klaviyo has an API endpoint called “Add Members to a List” where you can add each profile from Account B into Account A.
In other words, you can add contacts from Account B into a List in Account A for the purpose of excluding it whenever you send a campaign to Account A - or create a Segment that does this (Is in List A, but not in List B ).
This of course requires some technical/development resources to build and maintain the code or script to do this, so if you have access to it, you can have them explore the Klaviyo Developer Portal to learn how to get started.
If you want to look at other non-technical methods, you can look at some of the middleware tools like Zapier or Alloy that can connect the two Klaviyo Accounts to do something similar.
Thank you. That response is very helpful.
I see that Klaviyo has a tutorial about how to use the Klaviyo API. This sets me on the right path.
Really appreciate your thorough response.
