Model for balancing 2 sport teams with multiple players?
There is some lack of information on your post.


Does it take long time to try a match? (can I do 10.000 simulations or matches in minutes?)
What's your goal? Is to create teams that are as equal as possible?
Do the players really have better performance when they are together or you are assuming it?


But, I will try to give you an answer:
If it takes long what you can do is shuffle the players and measure the win/loss ratio, that resumes all you need, statistically speaking you will be conducting what is known as a experiment. If the players really "interact" you will have to measure the win/loss ratio by pairs.