At the HQ, we have TWO 7513 routers. At each spoke site, it has ONE 3600 router with two frac. T1s. One frac. T1 connects to 7513-A and another one is going to 7513-B. My question is, can I set up Multilink PPP connecting to two different 7513s? Or do I have to bring both serial links to the same 7513? Could anyone find a reference link for me? Thank you so much!