I didn't understand what you can't do, Bianca; perhaps a scan of the classic piece of paper could help
now I can't do a scan here, but take the first two staves of my 5/4 and 9/8 example; at the end it aligns them, whereas one expects the first to finish 1/8 later. What I would like is precisely for it to be like that without having to write a dummy time signature of 45/8, hide it, and re-edit, because in the final 45/8 time signature, it would write the eighth notes either all (on both staves) grouped in threes, or all in twos, or all single, and then I go crazy with the accents. I don't know if I explained myself clearly
Practically my score responds to your request; clearly, you will have to fix the groupings by hand. There is no other solution with a finale, so even if you would like it, you have to do everything manually. But it can be done.
Anyway, an unconventional management of groupings could also be of interest in favor of graphic aspects more or less related to those strictly musical to a certain passage. I have some of my own scores without time indications, not aleatoric or almost. Therefore, a program can only move through clear rules and for business aspects that satisfy most requests. If you want to use an experimental notation... the more you will have to do manual editing. After all, musical pieces that resort to polymetry are an atom of the music that has been written and that (still) is being created.
