Managing data between Repeating groups

I have one repeating group a.k.a ‘‘source’’ made of reusable elements (connected to database to show products)
and second repeating group made of Multiselect drop down plugin a.k.a ‘‘Drawer’’

I need to connect them. So that when user choses product in Drawer. That product disappears from source. (or make it somehow else)

1st picture shows state before selecting.

2nd picture shows desired outcome. Product is in dropdown and is hidden in source.

Thank you up front. I could not find it anywhere else on web and you are helping me to land a job :smiley: