do frats ever mix with sororities....

top generally only mixes with top
but for mid tiers is a lot more diverse. for example, some upper mid sororitys mix with a range of frats as low as sig chi/pi kapp but will also mix with frats as high as asig/pike, and then all the other frats in between as well. However, they definitely mix the most with the ones in their tier. Some sororitys also do mixers with club sports teams. lower sororitys sometimes with with club rugby/water polo and mid-higher sororitys sometimes mix with club hockey/lax/basketball

Sororities will sometimes mix with frats either one tier above them or one below like dg and pike and asig will mix and like sk and axo will mix w aepi and other top tiers sometimes and then du sometimes but like phi psi is never gonna mix with kd or deeph