What's the best way to add a staff to an instrument---but to add aux percussion?

Good morning,

I'm working on a percussion ensemble.

We've got a few more parts than people, so I wanted to double up mallet players with aux parts when their hands aren't busy.

Is there a smart way to create for, say, the xylophone player one staff for the mallet part and a second staff for the aux?

I have a master aux staff right now, and my hopes were to just drag the different measures up to each person when they've got time to knock claves or the like.

Thanks in advance.