Well, ConsumerTy, if your internal and outside numbers are crossing, Coral can differentiate local numbers and internal numbers beginning from the same digits. For example, by specific programming LCR, 5 you can make Coral dial outside number 2xx-xx-xx without prefix and - at the same time - dial internal number 2x-xx and so on.
The only inconvenience is that after dialing 2x-xx (internal number) Coral will wait interdogit timer (default, as I remember, 10 s). If user dials other digits, this call is outside, if no other digits received, thi call is internal.
