How long has it been since the new girl was added? If they sleep in the same room there is a certain measure of security going on. It may just take more time for them to settle.

In my experience with adding fully mature cats to a household, females are slower to accept each other and it may be years, if ever, before they groom each other tho they will usually play together (or at the same time) after a bit. Again, in my experience which may not be the rule, the males kept a low profile until the females decided how things were going to be sorted out.

Now, since the females are ragdolls it might be a size issue. Is Terry smaller than they are? He may be warning everybody off because he does not choose to be vulnerable to losing his spot as top-cat.

As I said, if they sleep near each other, I would not be too worried. Not all cats become buddies but most come to a friendly or at least civil accord.

Give Terry extra attention to help reassure him of his spot and to let them all see he is a valued member of the colony. Of course if he looks like he is hurting one of the others intervene, but it sounds as if he is just protecting his space. Let him see you play with the girls too so he learns everyone has an accepted spot.

Good luck. I've always had multi-cat households and there have been only a very few cats that didn't like or accept each other. Give it time.