How do I group some UV islands together when unwrapping?

I don’t know if this threads been made, I searched every which way I could for something similar. For example, if I wanted to model a face and I wanted to keep all the teeth grouped next to each other, and every time all the teeth separate because I unwrap everything. Pinning kinda works but it doesn’t move them to a new arrangement. Especially when I’m trying to keep parts of the UV islands in a rectified shape.