1) The moving feature might follow a predefined route (e.g., road), perhaps part of a network, and might change routes at known points (e.g., bus stops, waypoints).
2) Two or more moving features may be “pulled” together or pushed apart (e.g., an airplane will be refuelled during flight, a predator detects and tracks a prey, refugee groups join forces).
3) Two or more moving features may be constrained to maintain a given spatial relationship for some period (e.g., tractor and trailer, convoy).