Neutered male keeps mating my female rat

Question
My male rat is approx 6 months old. was neutered just over 3 weeks ago. Since then I have introduced him to my two females. One female is his sister whom he managed to impregnate prior to his surgery. there seems to be some forced grooming of her which she squeeks loudly about and runs from him plus some minor tussles. My other female he goes crazy for. Chasing her around and will copulate with her many many times. Since I plan to house all three together ( they had seperate cages and seperate play times before the surgery) (post surgery only have play time together) I'm worried that he will be forever after my ladies and won't give them any alone time to rest from his amorous self. Should I house them and hope that the copulation will stop? Please help, don't know if this is an odd scenario.

Answer
Normally boys will leave the girls alone once they've recovered from surgery; but it seems he's a little extra randy. With time this will/should settle down; but I'd be worried the cycle would restart as soon as you put them together again. Perhaps try leaving him with the girls for a week and see if he chills out, and if he doesn't; separate them.