My solution so closely resembled zaxo's that I removed it. The difference was that I used the existing code and changed the data by adding a data terminator, and changed

$CoreRegR{$key} = \@rangelist

to

$CoreRegR{$key} = [@rangelist]

After 10.104.2.5/27, just add an "END OF DATA" to the data and the code should work. This solution leaves you with an empty array ref for Server2 Name, instead of not including it with in the hash.