Hi felixpollan, Here's one way you could do it:
Subtract the positions of the rigidbodoes:
Vector3 normal = rigidBody1.Position  rigidBody2.Position;
Normalize the vector:
normal.Normalize();
Then, use this normal to apply a force to both rigid bodies:
normal *= <some factor>;
rigidBody1.ApplyForce(normal);
rigidBody2.ApplyForce(normal);
