Have you already import these Active Directory Group to vCOPS?
If YES.
You can create in the "custom-ui" an separate Group with these rights you want for these Active Directory Group.
If you want to grant access in the vSphere webclient it is more complex. You have to create a new Role with the permission for "vCops read only" and put these Role / Group at the top of your vCenter! BUT attention: do not propagate these Role to children