Hi Madan,
Help me understand your real concerns.
Are you trying to assign the role assignment approver in case of parent roles..?
If this is the case then yes, you can do this at the mass role import stage. You need to fill in the mass role import template with the parent role assignment approvers and confirm the check box for role assignment approver..rolr content approver as per your needs.
Let me know if you meant something else.
Regards,
Ameet