I keep groups of various kinosternids ( 3 types of kinosternon,4 sternotherus),in groups. The individuals will let you know if it works. I've only had 1 male on male razorback incident where I changed 1 individual & the new male was fine with the old male. I also had a male stinkpot who only liked his mate he attacked any other kinosternid placed in the tank, females included. the thing I find most plausible is visual barries keep down agression very well even with female on female or cross gender aggression. It should work with space & visual barriers even if females are introduced, but there would have to be more females then males.