Hi, I have 3 boy/girl pairs. When I just had 2 pairs, I did try to bond into a quartet, but gave up, as the 2 girls made it clear they would never get on. When I took on the 3rd pair, I hoped that they would make a quartet with on of the other pairs, but it became clear very soon that would not happen, and I’ve had to adapt my house to manage 3 separate pairs – doable, but hard work!
It is however quite possible to have a bonded quartet, or even bigger groups. I think this would depend on the various personalities of the buns, all my 3 girls are very dominant buns, only accepting of their own ‘husbuns’.
If you do decided to take these two on, you will need separate cages/runs until they are bonded, neutral territory to bond in, plenty of undivided time to spare, and a way to keep all the buns separate if bonding doesn’t work out. Also, be aware that bringing new buns into a home has been known to cause problems in the bond of buns already living in that home. Worst case scenario, could you manage with 4 solo buns, even on a temporary basis? And if you end up with 2 bonded pairs, how will that work with free roam? Each pair won’t just stay in one half of an accessible space just because there is another pair of buns the other side of the room!