MX records and Sendmail.cf with Redhat

["vic777 primenet com" <vic777 primenet com>]

I am setting up a network that will host multiple domains w/Apache using Redhat.  Reading in the "Red Hat Unleashed" book about MX records they state the proper syntax to have a particular host accept mail for the whole domain is:

domain.com	IN MX 10 hostname

Per my understanding, this would direct all incoming mail to to that particular host if destined for the domain (so mail to user domain com would go to this machine, versus the more specific user machine domain com).  Is there something that also needs to be done in the sendmail.cf file to accomodate this?  Also, can multiple MX entries be made for different domains pointing to the same host machine?  For example:

domain.com	IN MX 10 hostname
domain2.com	IN MX 10 hostname (same hostname)
domain3.com	IN MX 10 hostname (same hostname) ... etc...

I have tried to find information pertaining to this, but can't find anything readily.  Any input is greatly appreciated.  Essentially, what I am trying to achieve is being able to host multiple domains with Apache (using virtual servers) AND also being able to accept mail for these 'hosted' domains.
TIA,
Vic