With a t1, you need a dti card (with clock) or a tli card with a csu/em module combo. First one is easiest, second is cheaper. Order the t1 as esf/b8zs/loop start. Program them for 2nd dial tone and in their own trunk group. When you access the trunk group, you will hear dial tone from the distant switch. You'll have to read up on numbering plans....too much to go into here.
And oh yes, it is viable.