I don't have any experience with this situation (I don't have any experience with GPs actually; I love them but I'm not in a position in my life where I am comfortable with having an animal [I'm a college senior/sophomore (complicated), the boyfriend is moving across the country and wants me to join him for the summer, and I have no idea where I'm going to live next year]) BUT! I would assume their ability to get along really has to depend on the guys. Separation definitely seems like the right move, given their tendency to fight. However, it could just be that they need to get past puberty (as everyone else is saying) and they'll calm down and stop fighting, and you can put them back together. Or, they wont stop fighting, and they'll be solitaries, as
@Gigabyte said. I've mostly heard of people trying to pair young pigs with older pigs, just because the older pig will kinda put them in their place and teach them how to be a guinea pig before puberty, and then they're settled in their ways with the older pig being "boss-man/woman". I bet they're both trying to be boss, but neither really knows how to, so they just squabble. Plus, boys are just silly anyway
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These are just some musings, but I wonder if it is better to keep them in view of each other, or not. It may just aggravate them to see each other but not be able to get at each other, to fight for dominance (as shown by them ripping at the grid separator), or it may satisfy their social needs without being dangerous. But then, even if they cant see each other, if they're in the same room they'll be able to smell each other, which would lead to scent-marking as they both try to "claim" the room. I wonder what someone who has experience in this situation (complete separation of cages vs. some visual contact vs. same room vs. etc) has to contribute for you.