can members have multiple registration using the same password?

I’m not sure what the wishlist plugin is but I think the best way to accomplish this may be to use custom user metadata.

Such as adding “enrolled_in” to the meta_data then check for the value.

<?php if is_user_logged_in(){
global $user_ID;
$member_level = get_user_meta($user_ID, "member_level", true);

    //just mye1
    if($member_level == mye1){
       //Show mye1 content
    }
    //just mye2
    else if($member_level == mye2)
     //show mye2 content
    }
    //both mye1 and mye2
    else if ($member_level == mye1 && $member_level == mye2){

    //show both content
      }
        //not a member
      else{
        //logged in but not member you fail at life
      }
    }
?>

see: http://wordpress.org/extend/plugins/custom-metadata/ and http://wordpress.org/extend/plugins/add-user-meta/ for a few plugins