Segment Tree Designer

I've created a segment tree with 3 target cells.  Each target cell is to receive one of 3 promotions.  Each promotion will be delivered through one of 3 campaigns. 

I thought I could associate the segment tree to each campaign, and allocate a different branch/target cell to each campaign., but I'm finding that once the tree is used in the first campaign, it is no longer available for selection in the other campaigns.

How do I allocate target cell #1 to campaign one; target cell #2 to campaign two; and target cell #3 to campaign 3? 

Any assistance will be appreciated!