Theoretically, I suppose any of the southern gates could be used for a CTA arrival as long as the others west of them are also CTA arrivals, being bussed or have already disembarked and are boarding, as long as the doors can be set up correctly (I haven’t noticed where the doors could be closed off). The same could apply for domestic after the NE corner of T5A, with the obvious theoretical limit being where the FCC and U.K. Border are situated, and where the lockable doors are.