... that can turn these filters ('192\.168\.200\.|10\.10\.200',',SEVERE,') into this form ...

grep {/,SEVERE,/} (grep {/192\.168\.200\.|10\.10\.200/} (<$FILE>));

Have you tried it?

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @stuff = qw(
   A C B:Mild C:Severe B A:Severe Etc B:Severe And So On
   );
 ;;
 my @out = grep /Severe/, grep /A|B/, @stuff;
 dd \@out;
"
["A:Severe", "B:Severe"]
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