The Internet needs QoS internetworking to become QoS aware in the end-to-end sense. We address only one issue of this - adaptation of the differentiated services architecture, in particular, dynamic creation of DiffServ virtual boundaries. Our solution is fully distributed and data driven, therefore it could be considered as QoS ad hoc internetworking on contrary to statically configured DiffServ. The proposal is two fold. First, to support invariance under aggregation we suggest to maintain Per Domain Behaviours (PDB) based on Per Path Behaviours, and, second, to use group communication based on native IP multicast for needed QoS signalling and resource control. The paper shows that due to flexible grouping policies the approach has high scalability and good deployment potential.