Configuration with the DPI / PCEF,
3GPP OCS and PCRF will be vendor specific.
As a suggestion I would use the different IP Flows (SDF-Service Data Flows) with a QCI. PCC (OCS/PCRF using the Sy) will then Rate and charge the session using Diameter Gy.
At the Core Network layer the Rating Group – RG – is used to group a set of Services. The Service Identifier – SI – will be used by OCS / PCRF to Rate and Charge for the ongoing session.
As you will have MSCC you will need the Diameter Gy interface.
VBR/ Wallis Dudhnath