use strict;
use warnings;

use File::Find::Rule qw( );
use File::Basename   qw( basename );

my %files;
for (
   File::Find::Rule
      ->file()
      ->name('*.rtf', '*.ftp')
      ->in('.')
) {
   my ($name, $ext) = basename($_) =~ /^(.*)\.(.*)\z/;
   push @{ $files{$name}{$ext} }, $_;
}

for my $name (%files) {
   if ($files{$name}{rtf} && $files{$name}{ftp}) {
      print "$_\n" for @{ $files{$name}{rtf} }, @{ $files{$name}{ftp} };
   }
}