Help: Iterate through unknown number of elements, apply function

Help: Iterate through unknown number of elements, apply function

Hey there, newbie here...

Still getting a grasp on jQuery, so I'm probably overthinking or extra-typing...

Anyway, I have 2 select boxes. I can populate SelectA with items from a database, move the items from selectA to selectB and back again by clicking "add" and "remove"...
  <select multiple id="selectA">
        //populate with database information
  add >>
  <select multiple id="selectB"></select>
  << remove

        $('#add').click(function() {
                return !$('#selectA option:selected').remove().appendTo('#selectB');
        $('#remove').click(function() {
                return !$('#selectB option:selected').remove().appendTo('#selectA');

What I want to do is generate a set of these "selects" for each category in my database. I can do that through php and the use of a counter.... I get "selectA_".$ctr, "selectB_".$ctr, add.$ctr, and remove.$ctr as I should (i.e. first set of generated boxes would have the elements: selectA_1, selectB_1, add1, and remove1). BUT I have to add the click functions in the document ready function to this unknown number of elements (The categories can change in number as this is part of a user interface for database manipulation. I have to approach this as though I do not know how many such items exist.), so I'm trying my first jQuery each statement - without any luck....

HERE IT IS.... sorry if I butchered it... #input4 is the name of the form I have this scenario in...

                var addButton = "#add"+i
                var selectA = "#selectA_"+i+ " option:selected";
                var B = "#selectB_"+i;
                $("'"+addButton+"'").click(function() {
                return !$("'"+selectA+ "'").remove().appendTo("'"+B+"'");
                var removeButton = "#remove"+i
                var selectB = "#selectB_"+i+ " option:selected";
                var A = "#selectA_"+i;
                $("'"+removeButton+"'").click(function() {
                return !$("'"+selectB+ "'").remove().appendTo("'"+A+"'");

I'm a little lost at the moment and you could say overwhelmed. I just need a little bump in the right direction to regain my "get up and go." If you know how to store the values from a multiple select, that would be helpful too and maybe I'll just go back to my original idea instead of this...
Thanks in advance.