Hello!
It’s difficult trying to bond a couple of males huh? I’m going through the same thing! My two buns (Koala and Attila) at first seemed to get along, then had a really big fight. Afterwards they couldn’t even be in the same space without going at each other, which unfortunately set them back a bit. A good piece of advice I recieved when I came to these forums was to take the hormones out of the equation and neuter Attila (Koala was already neutered). After a long wait (both for Attila to fully develop, be neutered, heal, and for them to "forget" the fight) their ‘first’ introduction was in a bathroom.
However both had roamed around in there, so I think that is why they went straight at it again! A few of car rides (At first I had a friend drive because I thought that they would fight in the car. They didn’t but just in case.), and a truly neutral space later they can co-exsist. So far though, no real grooming has occured as I think they are working out who’s dominant. Unfortunately, BinkyBunny’s suggestion of fooling them into grooming by smearing banana on the head of a bunny did not work for me. (Though, it might work for you.)
One thing to watch out for is putting stuff in that may be chin marked by one or the other. For their area I got a new chew log and a new litter pan exclusively for that spot. Once, I brought in a big cardboard tube (8in dia ones) that they run through. Usually its in the common ‘solo’ bunny area, so I think they both thought it was their own and it caused a big scene. I wish I had my gloves for that one.
Lastly, I think this suggestion from the bonding journal of this website (where I pretty much got all this info) helped get them used to each others scents. It might help to switch their cages every other day.
When they start fighting is their anything that seems to trigger it?
I wish you the best of luck!
p.s. cute bunnies!