yes, of course!
Let say you want to start your solo under the soloist (or any other of the available instruments in BiaB), just click on the rlevant instrument, click on the chord sheet at the bar where the first action (for instance "mute instrument")should take place, then go in the right mouse menu and choose "Bar settings" (alternative press F5).
There you will see all available instruments.
Click on "mute instrument" option, specifying at which repeat you wish the action to take place (all or specific)
Repeat the same procedure after having clicked on the bar where the second action (for inst. resume instrument) should take place and: you have a solo or any other part playing where and as long (or short) as you wish. Simply briliant!
Have fun!
Bernard