#! perl -slw
use strict;

$/ = ''; ## para model see perldoc -q paragraphs

m[
    (?=^.*(DMZ|CRIT))
    (?=^.*host_name\s+(\S+))
    (?=^.*address\s+(\S+))
]sx and print "$2 [$3] is a member of $1"
    while <DATA>;

__DATA__
[snip... your sample data here]

##</code><code>##

C:\test>junk
denlas02 [146.xxx.xxx.xxx] is a member of DMZ
ppplas12 [10.50.33.26] is a member of CRIT