How to incorporate multiple MPC class into single MPC class?

Hi,

   i have requirement to create multiple MPC and DPC for 12 RFC finally i have to integrate whole MPC into a single MPC class,Is it possible to integrate multiple MPC class into a single MPC class? or i have to create a single MPC class,I tried to integrate entire MPC into single MPC class when i registering im getting error " Access via 'NULL' object reference not possible."  entity_type is not creating in second level class.i know if i use single MPC class it will work my question is multiple MPC is possible or not if it is possible please tell me the way how to integrate.

I have attached a Dump image for your reference.

Thanks.

Lokesh Srinivasan.