GoCentral website - multiple admins?

I have several different domains and several different GoCentral websites using Website Builder.

 

Can I assign someone else (possibly multiple people) to have administrative rights ON ONE OF MY SITES ONLY?

 

To be clear - I can see how to "delegate access" to another user, but this gives them access to my entire account including all domains, email, etc.

 

I want to be able to allow someone else to edit one specific site, BUT NOT have access to the rest of my account.

 

How can I do this?