socks marble and cocoa

i want to try bonding the three of them while cocoa is still small but marble (the younger of the 2 bonded males) is terrified of cocoa!!
any ideas??
tried blocking them behind sofa but there was a small quarrel between the 2 (marble and cocoa)
socks accepts the little one and grooms it lovely
should i put them in bathroom and leave them to it??

:wave:Are they all neutered? Are they all boys?

the two older ones are both boys and were neutered about 8-9 weeks ago
the little one is not yet 12 weeks so finding it difficult to sex it at the minute!!!
hubby has a hunch that its female!!