Get more mice, that should help solve the issue. You can keep about 1.5-1.7 in a ten gallon tank and they do just fine.

Separate them for a bit, then place everyone in a freshly cleaned tank at once, and put them in a dark place. Yes, they may squabble, but I've rarely had problems letting them work it out on their own. You can even get a squirt bottle with water in it and let the offender have it if they start a fight. They get the picture very quickly, LOL.

Oh, and I've had some groups go as long as 2.5-3 months before I even saw pinks, so just give it a little time. Definitely leave them alone except for when you clean! They stress a bit easily.