open(my $fh, "<", $ARGV[0]) or die "\n$0 Error => $^E\n";
my (@records,$rec);
while (<$fh>) {
   unless (/^\d+\s+/) {  $rec .= $_; next }
   push @records, $rec if $rec; $rec = $_
}
push @records, $rec if $rec;
close $fh;
# Now each item of @records has the lines you're looking for