LAG with 2 different ISP's and network addresses

I am trying to setup a LAG with 2 different ISP's that give me different network addresses, for instance:  63.xxx.xxx.xxx and 100.xxx.xxx.xxx.  I get the error "All ethernet ports in a LAG must be assigned to the same network".

Is it possible to setup some sort of VLAN or something so each WAN port can be LAG'd ?