Hi,
you can rotate around an arbitrary point using RotateAround action.
but likely it will be a lot easier if you parent your units to a dummy group, then you move each unit in local space, and you can control the global position and rotation using the dummy group. that would be how I handle it, else I would go with an OOP, where each unit control itself, but that's a lot more complex to setup.
Bye,
Jean