Grouping adjacent instruments, and a minor suggestion about rehearsal marks

In conductor scores, there are some, usually 3 to 4 "groups" to divide up different kinds of instruments, and increase readability. See the attached for example. It is a little blurry, but I guess still helpful.
Usually, every group has its own rehearsal marks and tempo marking. Also between groups, the staff distance are larger. I'd like to request for a feature that:
(1) Allow users to group adjacent instruments
(2) Allow users to format overall group distance like with staves or systems.
(3) Allow users to display text marked with "system flag" to simultaneously display onto every group.

Because:
(1) Conductor scores are extremely long. It would be really tiring to put spacers on every single page.
(2) The same things go with rehearsal marks. For tempo, one even has to hide the real one, and create fake ones to avoid multiple tempo marker in the same place.
(3) That being done, one has to work really carefully to avoid those format to change accidentally.
(4) When splitting into parts, one has to hide all the redundant texts used to format the conductor score.

Thanks for any response in advance.

Side note: it would be great if Musescore features square rehearsal marks. Most of the sheet I've seen use square ones for letters.