Easily selected review of (listening to) parts in sections & beat-by-beat

I would like to EASILY "step through" i.e., listen to a part, or parts, one or several beats at a time - and only the instruments I need to hear. This is a 2-part request for a new feature:

1.) Selection: I would like to use instrument and section selection, as is possible already and then just select "play." (without having to use the cumbersome Mixer to paw through the orchestra to flip certain instruments to "solo". Then change my focus back to my work, only to have to switch my attention back to the cumbersome Mixer, etc., etc.)

2.) I would also like the ability to listen to the selected parts beat by beat, "stepping" through time.

(Sure, You can step through ONE staff chord by chord using the Right Arrow on your computer keyboard. But having to have the full mixer in a separate window and toggle between your score window and your mixer window using the function key F10 is clumsy and takes your focus away from your work.)

Thank you.