Constraints Manager, not sure how to define this constraint

Hi all,

I"m still coming to grips with the Constrains Manager and I've run into a constraints definition problem I cant wrap my head around.

I have a design that has a pair of nets (NetA and NetB) that between them use the Default Constraint set, but from them to the rest of the world requires 1500V creepage values.

I have defined a Spacing Constraints set, SCS_1500V which contains NetA and NetB, with creepage values suitable for 1500V.  The problem is, that the SCS_1500V is also applied between NetA and NetB producing a few hundred DRCs.

My question is, how do i define constraints that prevent the SCS_1500V rules applying between NetA and NetB, but continue to have the SCS_1500V between them and the rest of the world?