It would be far better to just produce the sets you want than to produce more than you want and then throw some away. The sets you are after are quite easily produced iteratively with a couple of loops:

After the fog cleared:

#! perl -slw
use strict;

sub adjSets{
    my $min = shift;
    map {
        my $start = $_;
        map {
            [ @_[ $start .. $start+$_ ] ]
        } $min-1 .. $#_-$start;
    } 0 .. $#_ - $min;
}

sub adjSets2{
    my $min = shift;
    my @rv;
    for my $start ( 0 .. $#_ - $min ) {
        for my $len ( $min-1 .. $#_-$start ) {
            push @rv, [ @_[ $start .. $start+$len ] ];
        }
    }
    return @rv;
}

print "@$_" for adjSets( 2, 'A'..'E' );;
__END__
c:\test>689189
A B
A B C
A B C D
A B C D E
B C
B C D
B C D E
C D
C D E
[download]

Update: Ignore below. T'was too early in my day, so just downvote this. Comments unnecessary :)

Early morning brainfart