#!/usr/bin/perl
use Data::Dumper;
$Data::Dumper::Indent = 1;

my $ary = [];
my $i   = -1;

while (<DATA>) {
    chomp;
    s/\r//;
    /^Mtf.*\s(\S+)$/ and push @{ $ary->[++$i] }, $1; # next array
    /\s+St f\d+/     and push @{ $ary->[$i]   }, $_;
}
print Dumper($ary);
__DATA__
- your data here -