Discover Multibranch Branches *plus* one extra

Hey there. We are currently running version 2.452.2 and I have a weird request:

We set up a multibranch pipeline, set to check every branch. But our worker machines got too many things to work and that put a delay on when the checks are done.

To reduce the number of builds, the developers suggested we change the discovery to “Only branches that are also filled as PRs”. That, indeed, reduced the number of builds, but it seems to prevent us to force checking specific branches – like our “develop”, which some people commit directly for small fixes, and have no PR open.

Is there a way to keep the “only run on branches with PRs but also a specific branch”?