I see currently I am at the point where her and sasha have a fight in sasha's shop.Umm if your talking about the first event with Palla you aren't even close to when you can get the harem. You need to basically finish her route and go on a date and raise her kp with the appropriate limit raising choices. Sounds like with Sasha you're ok just need to move Palla's route further.
If you're talking about the event when Sasha's fucking Palla with a strap on that is the only event for it there isn't anything else.
I'll try completing her route first then