Adding new activities to an exisitng P6 Baseline - without changing existing activity baseline

Hi I hope someone can advise,

I am creating a schedule which has 5 workstream leads doing different things, I would like to create a schedule that includes all their activities but they will not be available at the onset.

I would like to add say workstream 1 then add a baseline for that , then say next week add work stream 2 activities  and add to the first baseline but not re set the workstream 1 baseline - is this possible?