With my sorority, size didn't really seem to matter when it came to aggression. It usually all depends on your girls' personalities.
You're definitely going to see everyone bullying one another for the next couple of weeks, so it's perfectly natural. I would let her out and see what happens. If she's separated too long, she'll probably end up being the bullied one. I know it sucks to watch, but it's probably better to let them get their aggression out, and if something gets out of hand, break it up. Just keep a close eye on them.
If you have one or two that are still being super aggressive after that two week period, take the meanie out. At least temporarily. I had that problem with Daiquiri (one of my smallest) ripping the others to shreds. I gave her a "time out" in a one gallon tank for about a week. I put her back in, and now she gets along just fine.
The whole "setting up the sorority" process is annoyingly difficult, but it'll be definitely worth it in the end. :)