Making a hash with groups of IDs

jemswira has asked for the wisdom of the Perl Monks concerning the following question:

I have this project that's kinda urgent and I still have not much idea how to do it. What i'm supposed to do, is to take a file that looks like this:

# STOCKHOLM 1.0
#=GF ID   1-cysPrx_C
#=GF AC   PF10417.4
#=GF DE   C-terminal domain of 1-Cys peroxiredoxin
#=GF AU   Finn RD, Coggill PC
#=GF SE   Gene3D, pdb_1prx
...
#=GS A3EU39_9BACT/160-195  AC A3EU39.1
#=GS Q7VQB3_BLOFL/159-194  AC Q7VQB3.1
#=GS Q057V5_BUCCC/160-195  AC Q057V5.1
#=GS A5CDZ8_ORITB/160-195  AC A5CDZ8.1
...
//
Similar set of data with different numbers.
[download]

so the final file i need is one with this:

A3EU39 | PF10417.4/ PF10000.3
Q7VQB3 | PF10417.4/...
[download]

I also have a file with a list of these 6digit numbers/letters and i have to arrange them in that order. At first i wanted to go through the file each time, but both files are large so i have to try and just run once through. So i was thinking a hash. like a hash with Q7VQB3->PF10417.4/.....

But to be honest, i have no idea how to. I'm sorry but i'm really new. i was thinking

my %hash;
open PFAMDB, "C:\\Users\\Jems\\Desktop\\Perl\\Pfam-A.seed" or die $!;
#thats the main file.    
while (my $pfam=<PFAMDB>){
    my @units= split /#/,$pfam;
if ($pfam=~ =GF AC){my $pf=$pfam;}
if ($pfam=~ \sAC\s){if exists $hash{$pfam}{$hash{$pfam}=$pf}
else .....
[download]

so this is where i get lost. can i push a new value to the end? also, will this work in the first place? Im sorry. but i'm still new D: please help me? Thanks!

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