I am new this forum so thanks for reading my question and thanks in advance for any advice you might have.
I have 5 zebra finches. 2 males and 3 females. I have a large flight cage for them (about 2x3x5 feet). Anyway one of the female has been getting picked on, and this has been happening since before I got them. Not long ago she was lethargic and seemed pretty bad so I took her to the vet. 10 days of antibiotics later (which I can assure wasn't easy to administer to a bird so small!) and she seems to be back to full health.
However, I had her in a spare cage away from the others during that time. Just about an hour ago I put her cage next to the flight cage and she freaked out! She wanted to get back with the others so badly that she SQUEEZED THROUGH THE BARS OF THE CAGE AND GOT LOOSE.
So what do I do? What if I put her back with the others and they hurt her again? Or - what if I leave the 2 cages side by side and she hurts herself? Would it be too stressful to keep her totally isolated? All options seem bad

Thanks for all of your help and any advice you might give! I love the zebra finches and want to do whats best!