ARS web password modification

I need assistance with trying to set up password control for our helpdesk.

So our help desk only uses the Web console in order to change passwords.

what i am wanting to do is to lock access to change the password for all helpdesk users, however there will be a few users who will have access to do it. i tried to mofidfy the template in the ARS console however the property object will not allow you to just use it as a read only object.

does anyone have any suggestions on how to go forward with ?