Try moving a T1 unit close(Within T1 PD range) to Beacon A. You should get a teleport button for the unit you moved, which can be used to teleport it into the area close to the other beacon.
I believe the rule of thumb is you need 1 beacon to teleport to, and at the point of origin 1 beacon per tech level. Titan needs 3 beacons to initiate a jump, striker needs 1, Fatboy needs 4(possibly more).