You are almost there. With POTS lines you have to assign separate keys for each line appearance for each line in hunt.
In a PRI/Target line scenario, you only assign to single target line you have assigned the main number to (assume it's target line 125). In a PRI/Target line environment, there are no additional hunt numbers needed (or used), the one target line will ring into the system up to 23 times (the number of channels in a PRI).
You will dump all the previous line appearances you had for the POTS lines and in it's place you will assign line 125 as a A&R appearance on the set. As you press next there will be a new field appear that you didn't have before, it is an appearance field and here is where you will tell the set how many times you will allow this number to ring to that set (three might be a good number to settle on). The target line assigned to the phone is a DID, and cannot be used to dial out of the system with, it is an incoming line appearance only. Hope this helps.
Jim
"If I had known it would turn out like this, I would have become a locksmith" Albert Einstein
NCSS, NCTS, NCTE, CS1000E, Avaya IP Office, Mitel 3300 Basic & Advanced, 5000, SX200, NuPoint