Combined CIS2 Callback URLs

Good afternoon,
We have certification for using combined CIS2 for user authentication with PDS.
We have also more recently (in a later version) certified fully for separate CIS2.
When setting up applications with combined CIS2 (via the dev portal) we can only set one callback URL, when setting up for separate CIS2 (via emailing the relevant team) we can set multiple valid callback urls.
I assume the underlying system is similar in both separate and combined CIS2 so is it possible to have multiple valid callback URLs within combined CIS2 or are we restricted to one callback URL in every environment?
Thank you,

AFAIK, combined auth only allows a single redirect as that is handled by a different authz server that then delegates authn to CIS2 Auth from the API platform.
Separate auth gives you much more control over the authn process.

Thanks for the response Adrian