Filter input - only files with same relative paths

[james-cook]

Is there any way to filter input to allow only files with same relative paths through.
Something like the existing --match-basename but for paths?

i.e. a duplicate file is only found if it shares the same relative path - with an option such as --match-dirname...

Pseudo code:
rmlint <other options> --keep-all-tagged --match-dirname --match-basename DIR1 // DIR2

(This would only work/make sense with tagging I think, and --must-match-tagged would not be needed in this case as files must have the same relative path in any case)

[ttyusupov]

@james-cook , I've implemented something like this here: #640