Quadruped control through moveit

I am working on a simulation project of a quadruped robot. I am planning to do it using moveit! The problem here is I have to **fix the tip of the 4 legs to the ground** before moving the base of the robot to make the COM fall into the support polygon. I thought of doing it by defining each leg a sub-group of the base and giving **position constraints** to the tip of the legs while changing the pose of the robot from one joint-state to another. Is this possible? or is there a better way to do this? Can someone shed some light on this!