ForceBasic Coord. Object
The Dynamics Force object causes each object to exercise its own radial gravitational force onto every object within its reach (can be enabled per Dynamics Body tag via the Force List). This can be a attractive or repulsive force.
If you disable the Gravity in the Project Settings so that only the Dynamics Force object has an effect, an orbiting effect similar to that of the planets (or an agglomeration) will result if they are moved towards each other with an initial velocity.