#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my @unpairedSidBinder = ( 'sid  1|FLPSDFFPS LLWFHISCL',
                          'sid  1|WIRTPPAYR YVNVNMGLK',
                          'sid  2|FLPSDFFPS LLWFHISCL',
                          'sid  2|FLPSDFFPS ELMNLATWV',
                          'sid  7|FLPSDFFPS ATVELLSFL',
                          'sid  7|VWIRTPPAY LLSFLPSDF',
                          'sid  9|VWIRTPPAY LLDTASALY',
                          'sid  9|FGRETVLEY PSDFFPSVR',
);

my @combined = ();
my $last = q();
for my $item (@unpairedSidBinder) {
    my ($left, $right) = split /\|/, $item;

    if ($left eq $last) {
        $combined[-1] .=  " $right";

    } else {
        push @combined, "$left|$right";
        $last = $left;
    }
}

say for @combined;