The answer is yes, what you seek very possible. The key however is that the PRI is sending a number across to the UCM. The number represents the DID that the caller used to reach you, but when sent to the UCM, it may not be the same number as what the caller dialed. In other words, the caller may have dialed 9995551212, but the PRI may have sent 5551212 or simply 1212 or something or length of digits.
When trying to send direct to an extension given a certain DID that the caller dialed, the task is to determine what the PRI sent and then match that EXACTLY in the UCM inbound rules. You can then create range rules once you have discoverd the secrete such that iy have 100 DIDs you need not create 100 individual rules.
The guys who posted before me provided the info on how to setup, but the key is knowing the format of the numbers sent so you can route each to your need.