My experience of two bucks and a doe was unsuccessful. I already had the bucks and acquired another rabbit. I was told it was a boy and it turned out to be a girl. Nibbles and Donut both wanted to be Hanks friend (named before we knew it was a girl) and although if one boy was out with Hank all was fine, if they were both out, Nibbles would chase Donut. Whilst there was never any fighting as such, Nibbles wanted to be with Hank and sat on the grass almost flaunting his friendship with Hank to Donut, who had to live in the borders. It took a few days for us to actually realise what was going on, we just thought Donut was in the borders to get out of the sun. I then noticed the minute Donut stepped onto the grass, Nibbles chased him. After noticing this happening, we had to have one boy out at a time with Hank. This worked fine.
This is obviously my experience and Nibbles was no where near as laid back as Donut. Perhaps this is why it didn't work. I really don't know.
It was a shame though, as Nibbles and Donut were great friends before Hank appeared.
She unfortunately died shortly after we had her (told brain parasite) and Nibbles followed suit a couple of months after (also brain parasite). Thankfully Donut survived after living on panacur for several weeks. He now lives with Bailey, another boy, and I personally would not get a girl to join them - even though Bailey is as docile as Donut.