Probably won't as the oung mothers will probably attack the newcomer and then you just messed up the whole colony again. When you figure out the've been beating on the experienced mother and you put her back to the old group, the old group won't recognize her and attck her as well. So you may have to just put it down if you have already done it or let it live in its own enclosure and let her raise a litter and keep the young with her to mature and then you'll have another established group.....
If you haven't don't.
Some mice never get over it and will continue to kill. I say give them another chance to have 2 litters total and see what happens (or maybe 3 litters total I wouldn't though).....You may also have a female that is a lone serial killer. Whenever babies come out she'll go and kill them for no apparent reason. So it may be hard to find out exactly who is doing it. I had a female here kill her litter about a month ago and she killed all of hers. I took the fresh dead bodies and fed it to the monitor. The the other two had litters 1 day apart form eachother and the killer mom started taking care of the young with the good moms.
Personally, I am through with the mice thing aqs I can use rat pups and fed one of the mouse moms today and froze the others. They just smell to much, are nasty, and to nervous compared to rats. I say if you need mice then go the route stated earlier. If you can get away with rats go with rats hands down. They are much more forgiving......