Multiple virtual host DNS question re: reverse DNS

If you use a single IP address for all hosted virtual domains, then no. A reverse PTR record will point to a single domain, usually that would be the hosting server.

server with single IP (eg 192.168.2.2 for this example) hosting multiple sites:

myserver.domain.tld           A record -> 192.168.2.2
   |- something.tld           A record -> 192.168.2.2
   |- www.something.tld       A record -> 192.168.2.2
   |- other.tld               A record -> 192.168.2.2
   |- www.other.tld           A record -> 192.168.2.2

reverse PTR record for 192.168.2.2 -> myserver.domain.tld
MX record for all of the above -> myserver.domain.tld

now, if you have multiple IP addresses on the server, you can use them to separate the hosted domains.

server with multiple IP addresses hosting multiple sites:

myserver.domain.tld           A record -> 192.168.2.2
   |- something.tld           A record -> 192.168.3.3
   |- www.something.tld       A record -> 192.168.3.3
   |- other.tld               A record -> 192.168.4.4
   |- www.other.tld           A record -> 192.168.4.4

reverse PTR record for 192.168.2.2 -> myserver.domain.tld
reverse PTR record for 192.168.3.3 -> something.tld
reverse PTR record for 192.168.4.4 -> www.other.tld
MX record for all of the above -> myserver.domain.tld (or you could use the individual IPs, depending on how the MTA is configured)