Create a common datum out of two single datums in GD&T Advisor (ISO GPS)

We have defined three datums:

1. A - a planar surface with a flatness requirement
2. B - a single hole, perpendicular to A
3. C - a slot

To account for the "ISO Bug" (Annex I in ISO 5459:2024) , we want to use the position tolerance (see red box) with a DRF of A|(B-C) instead of A|B|C.

But somehow Creo GD&T Advisor does not let us create that DRF via the “Establish DRF” functionality:

Is it possible to create custom DRF in GD&T advisor?