I totally agree with 5 little monkeys. Keep the children/parents that are easier and can "go with the flow". I've been in this situation and ended up getting rid of a dcb whose mother I didn't get along with and was an all around a pain in the ass.
I felt so much better after that...my stress level went way down and I knew that I did the right thing.
No amount of money will make up for your sanity and peace of mind