Hi Jeff,
Yes this is possible since the Enforcers use the same management server list(s) method from the SEPM server policy library. Just select an appropriate server list. See pic below. Of course if you are doing LAN Enforcemen and fail over to another site, it ma indicate more than just a SEPM down, then you may need to make sure all RADIUS parts list RADIUS cliens/shared secrets for the other site.
Cheers!
Josh