## in file Foo.pm:
package Foo;
use strict;

use Class::Multimethods;

multimethod new => ('$')
 => sub {
     print "I'm the constructor for Foo\n";
     bless {},$_[0];
 };

1;

##in file Foo2.pm:
 package Foo2;
 use strict;

 use Class::Multimethods;

 multimethod new => ('$')
  => sub {
         print "I'm the constructor for Foo2\n";
         bless {},$_[0];
  };
1;

## in main.pl:
 package main;
 use strict;
 use Foo;
 use Foo2;

 Foo->new();
 Foo2->new();

## ==== OUTPUT ==== ##
#I'm the constructor for Foo2
#I'm the constructor for Foo2

##</code><code>##

package Foo;
use strict;

use Class::Multimethods;
*Foo::new = \&_newFoo;

multimethod _newFoo => ('$')
 => sub {
     print "I'm constructor for Foo\n";
     bless {},$_[0];
 };
1;

## Foo.2pm
package Foo2;
use strict;

use Class::Multimethods;
*Foo2::new = \&_newFoo2;

multimethod _newFoo2 => ('$')
 => sub {
     print "I'm constructor for Foo2\n";
     bless {},$_[0];
 };
1;
## Now, it works as it should be. Of course with also other 
## overloaded methods like _newFoo('$','HASH'),_newFoo2('$','$')