Hi Mike
So when we are getting a DS3 Link from a provider is that an IP Circuit on DS3 or a P2P DS3 between any two points means just a L1 Circuit.
If the DS3 is a P2P circuit then I don't think this DS3 can be reassigned as P2P T1s to customers. What can be done is that this T3 can be used as an intermediate aggregation point for the P2P T1s running between multiple customer sites using DXCs but the last mile T1 would be a separate physical media and the T1s would be mapped onto the T3 using DXC.
If this DS3 is an Internet IP Link then again it can be only used to aggregate and send traffic of multiple downstream customers to upstream ISP and the downstream customers would be on separate physical IP T1s.
Hope this provides some insight to your traffic requirement.
Regards
Varma