public void setCollideWithGroups(int collisionGroups) {
        this.collisionGroupsMask = collisionGroups;
    }
Directly set the bitmask for collision groups that this object collides with.

@param collisionGroups the desired groups, ORed together (bitmask,
default=COLLISION_GROUP_01)
jme3-jbullet/src/main/java/com/jme3/bullet/collision/PhysicsCollisionObject.java