hi Guys, 
I had a Visual Workflow which needs to run without Considering the permissions.   I need to Run the Visual Workflow from Apex as a Particular User with the Higher Permissions. 
Synario: Create one GroupMember record on the Public Group through Apex.
Error Message: INSUFFICIENT_ACCESS_ON_CROSS_REFERENCE_ENTITY: insufficient access rights on cross-reference id.

Please help me Regarding this....................