I agree, I don’t think you’ll find a suitable big enough cage for 3. I think a condo is the way to go. Or use an exercise pen as is or to build a condo style habitat. Another option would be adjoining some large dog crates.
Just a “heads-up” in case you are unaware, don’t put your male rabbit in with the girls for a month (2 months is better!) after his op as he will still be fertile for a time. If the girls are desexed, then it’s not an issue. But he may show some increased hormonal behaviours right after neuter. That’s not unusual.
As for them living together, some rabbits will get along from the get-go, but more often then not, there will need to be a bonding process before they can all co-habit peacefully. : ) Forgive me if I’m telling you things you already know! I usually like to mention these things regardless, as it may help anyone else reading that is in similar situation. And it just may save someone the shock and cost of a suprise litter of rabbits, plus avoid rabbits becoming injured as result of fighting from being housed together too prematurely.