Hello, Tokyo2040:
I understand that you would like the DLP agent to change groups based on IP address as your Group Condition. This is not currently a feature of the product.
However, you could consider adding an endpoint server to each of the branch offices, and use the Endpoint Server group condition to allow the agent to automatically change between groups*.
*This may be ineffective if endpoint servers are all routable between branch offices, as the agent would attempt to reach the first server defined in the list first.