How to set multiple domain and backend access

Hi Team,

I have questions regarding multi-domain.

We need to set up multiple domains (not epi multisite).

a)how to set up multiple domains for the epi site?

example:

1.domain 1 -(site,backend)

2.domain 2 -(site only)

b)Need to restrict the domain2 site epi backend access. How to restrict that access?

c)Is there any license update need for this multi-domain?

Advance thanks,