TG 3956 was active here today on the VHF Imperial site. They were doing radio checks with all the 'Regions' listed under Moswin.
I heard one user refer to the TG as MHA2 whatever that may stand for. I have no idea if this is what the OP heard but it could be as St Louis City is a Moswin site. The person running the show had a RID of 1300999.
Looking at my notes, it appeared the person doing the calling was calling for the Coordinators of each Region in the state.