toes bones

I just made a simple character with bones, the lower leg is IK, everything works fine, but I added toe bones afterwards, how to I assign the toe bones so that I can move the toe bones without affecting the other bones. I want my leg to make steps but when the foot is going back, I want the toes to bend a little. I tried to ctrl P the toes to the mesh, but when I move my lower leg, the lower legs stretches and the food does not move.

forgot to mention that the toe bones are contected to the lower leg that has IK