How can i stop characters from pushing each other

i am writing a 2D game. when characters can move around the background using mutlitouch. However when they collies with each other they just push each other away i tried to set velocity to zero at oncollisonenter but then it stops for a second then still push against other character . i tried to set Velocity in on collisionstay then. my character can never leave the collision again. since it cant move. i tried also iskinematic way . it just let 2 char pass through. character controller seems to me a good way. but. i cant call oncollisionenter/stay/exit which i have to use it for playing audio doing animation.etc. So how can my character act like they are kinematic to each other. stop when collision and fight each other.