To use DMR Access Control you can add the following fields to your MMDVM.ini:

Blacklist= <comma separated list of source-id's to block on RF>
DstIdBlackListSlot1= <comma separated list TGs to block on RF and Network Slot1>
DstIdBlackListSlot2= <comma separated list TGs to block on RF and Network Slot1>
DstIdWhiteListSlot1=9 
DstIdWhiteListSlot2=9