I'm not familiar at all with Olandsk Dwarf. When I looked them up it looks like they are a bantam landrace from Sweden. I don't know why they would be any different from chickens.
Why do you want any rooster? What are your goals with those boys? The only reason you need a rooster is fertile eggs. Everything else is personal preference. Nothing wrong with personal preference, I have a few myself. But that is a want, not a need. I generally suggest you keep as few males as you can and still meet your goals. That's not because you are guaranteed more problems with more roosters but that the more roosters you have the more likely you are to have problems.
So what can you do? One option is to do what I think you want to. Keep them all together and see how it goes. Trust what you see more than you trust a stranger over the internet like me. It is possible things will work out, the more room you have the better your chances. But I'd have a Plan B ready to go immediately if it becomes obvious they need to be separated. Have some place to put them. When you need it you don't have time to build.
You can get rid of one, two, or all three of them. One may turn out to be too many for you if you go by behaviors. Get rid of means sell, give away, or eat. They are bantams and still really young so there won't be much meat there but they will be bigger than quail.
Prepare a bachelor pad. If the boys are locked up where they can't get to the girls they won't bother them. If they don't have girls to fight over they usually don't fight that much. You could lock two or all three boys up now but you should be OK with them all together for a while longer. But get that pen built now. When you need it you will probably need it in a hurry.
