Restrict access (cell level security) editable by power user

Summary:

To restrict data input on certain members in the period dimension (days), we have enabled cell level security to do this which works perfectly. Requirement now is that global finance users (power users) are able to update the restrictions (cell level security rule) on a daily basis.

It seems that only service admins are able to update the cell level security, which also makes sense. Are there any other options to facilitate the same (restrict access for end users on members from the period dimension)? We are using standard PBCS (NSPB) (in combination with NetSuite), hence groovy is not an option.