Lip locking agression or love?

Hi everyone,
Yesterday I brought home a new Kenyi to add to my collection. he is a much lighter color than my other two. Almost yellowish but not quite. Anyway, as soon as he was introduced into my tank he and my most agressive kenyi started lip locking. This went on for about 30 mins. Now the new addition has taken over the other Kenyi's favorite spot in the tank and my other one is away in the corner by him (or her) self. Is this agression and fighting for dominance or is it some sort of mating ritual? I have attached a picture of the 2 of them, but it really doesn't do them any justice. The new kenyi is on the left.
Also, my 2 older kenyi's don't come up to eat now with all the others. They linger at the bottom in their separate corners. Should I be worried?

Thanks for the reply. The new Kenyi gets along fine with the red zebras and the yellow labs so far. Today he went up to one kenyi and he (or she) layed down on one side as if playing dead. It weas really neat to watch. Now my previous aggressor is way at the top of the tank hiding between the filter and the tank. I couldn't find him at first and got pretty worried. I feel sorry for him

It's been 2 days and the new guy still won't give up! He is relentless and chases my other 2 kenyi's around constantly. They have already let him be the boss as they are always hiding. Should I wait it out? Will this pass? It's like he is purposely looking for them so he can terrorize them!!

Thanks for the replies everyone. I do feel a little better. It just looks so sad when my 2 kenyi's play dead whenever the "bad boy" is around. I guess that's what happens when you have agressive fish.