Merge Only Specific Files From Forked Repository?

In our research group we have a common repository which all group members have an own fork of. Everybody does development on their own fork on work-branches and keeps their master as a copy of the parent repository.

Occasionally it would be helpful to merge only some of the files from the fork to the parent repository to keep the parent repository up to date with files that are interesting for all group members. Is it possible to create a merge-request for only specific files?