I need to load balance IPSEC with GRE over multiple T1s. My current solution is to use two routers, one to hold the physical T1s and the other to form a single SA back to the home router. If I use one router, the traffic does not load balance over the multiple SAs that are formed to the home router. Is there a way to bundle the T1s into a single, virtual interface so that I only use one SA?