To do it the easy way just use Realband or :

If you want to make your own or modify an existing Soloist, use the Soloist Maker (edit) module.

You can press F5 or..
"Breaks" for only some instruments

You can specify that some instruments not be affected by the break.

The coded names for the instruments are:

B for Bass

D for Drums

P for Piano

G for Guitar

S for Strings

To type a rest for all instruments on a C chord type

C.

To exempt instruments, add their letters following the break. For example, typing

C.bd (Bass & Drums will play only)

will put a rest on all instruments EXCEPT the bass and drums, or to put a held chord for all instruments except the piano, type

C...p (Piano only track will play during hold)