Hi @john12
I tried and definitely using the remove/add staff command method (that is unnecessary, in your case, since Dorico has dedicated and automatic Staff Visibility Layout Options) doesn’t influence the other instruments visibility of Page View.
I think here you are probably confusing page View and Galley View. As @Janus suggested, you always see all instruments in Galley view, to be able to enter the notes wherever you need, if you switch then to page view you will see what will be printed (and the Layout Options > Vertical Spacing > Staff visibility will be applied to Page View).
As @jesele and @DanielMuzMurray suggested, you can use the mentioned Layout Options to obtain what you need, automatically (and you can then set strategical System Breaks, as mentioned, to save more vertical space).
Here an example Dorico File that you can study and see if this is what you want:
marimba automatically hiding staff.dorico (812.8 KB)
There would be also the possibility to use Marimba 1 staff instrument, together with one of the the 2 Staves Marimbas, and write the music (in Galley view) to the desired instrument, and have activated Instrument Changes for that Layout (but, as mentioned, is not necessary in your case):
In case all our suggestions don’t give you the desired result, please, post a Dorico Project and explain what your are trying to obtain.
Here more information (especially #4):