Location Awareness while on VPN

We are trying to setup our SEPM 12 to connect to our internal sepm server when the laptop is connected to our internal network and when the laptop connects to our Cisco AnyConnect VPN.  Then when the machine is off-network (not on the local LAN and not on VPN), we want the laptop to connect to our external SEPM. We've tried what we think is all of the options for identifying the VPN connection by DNS server, subnet, gateway, DNS lookup, etc.  None of these set the location correctly for VPN connected laptops.  When the machine is put on the local lan, the logic connects the machine properly to the internal SEPM.  Any ideas what me might be missing or how to best troubleshoot it?