Here is a suggestion that shows you the basic idea. It's not exactly what you ask for, but this is not a free code writing service. :-)

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = MainWindow->new;
my $lastbutton = 'blue';
my $rb = 'blue';

my $rb1 = $mw->Radiobutton(-text => "Button Blue",
                            -value => 'blue',
                            -variable => \$rb,
                            -command => [ \&showRB, \$rb ])->pack;
my $rb2 = $mw->Radiobutton(-text => "Button Red",
                            -value => 'red',
                            -variable => \$rb,
                -command => [ \&showRB, \$rb ])->pack;
my $rb3 = $mw->Radiobutton(-text => "Button Green",
                            -value => 'green',
                            -variable => \$rb,
                -command => [ \&showRB, \$rb ])->pack;
my $rb4 = $mw->Radiobutton(-text => "Button Hot Pink",
                            -value => 'hotpink',
                            -variable => \$rb,
                -command => [ \&showRB, \$rb ])->pack;


my $but = $mw -> Button(-text=>"Preferred color", -command =>\&push_bu
+tton)->pack();

my $but1 = $mw -> Button(-text=>"Submit", -command =>\&update_script)-
+>pack();

                            
MainLoop;

sub push_button {

   foreach my $rb( $rb1,$rb2,$rb3, $rb4){
         $rb->configure(-state => 'disabled');
      } 

     $mw->messageBox(-title => 'Status',
                     -type  => 'OK',
                     -message  => "Status is :$rb:. Previous State was
+ $lastbutton");

}


sub update_script{
     
        $but1->configure(-bg => $rb);


      }



sub showRB
{
     print "Arg list is @_\n";
     my $state_ref = shift;
     my $state = $$state_ref;
     $mw->messageBox(-title => 'Status',
                     -type  => 'OK',
                     -message  => "Status is :$state:. Previous State 
+was $lastbutton");
     $lastbutton = $state;
}
[download]