What are their genders? Bunnies are very territorial and need to be gradually introduced and monitored on neutral territory. it can take a while. a male and female would be easiest to bond.

i belong to a bunny forum called etherbun that has helped many bunny owners learn how to giv.e their bunnies good care and a good life. here is the link main@etherbun.groups.io | Home

good luck!!