If the essence of the question is whether there is some kind of a cross-checking mechanism across SPG and MR for overlapping stays, I believe the answer is no - the "link" between the two is limited at this time to matching status and converting points to/from each other. As such, there is nothing preventing two concurrent nights across the two programs.

The remaining requirements, i.e. presenting one's self for check-in personally at some point, still apply for both rooms.