JQuery :: Validate Matrix Columns And Rows?

I'm trying to validade a table that has 20 checkboxes (5 columns and 4 rows) and that needs to have at least 2 checkboxes checked in each row and column.I've managed to create the validation for the row part (all checkboxes in the same row have the same name).I've also created a custom class rule (all checkboxes in the same column have the same class) but it doesn't seem to work. It only shows the row validation messages (labels that are display next to the last cell in each row) and not the column rule message.

Here is the code:

<form class="form_matrix" id="form_matrix" method="get" action="form_matrix_submit">
<table><tbody><tr><th></th><th id="col_1">Col. 1</th><th id="col_2">Col. 2</th><th id="col_3">Col. 3</th><th id="col_4">Col. 4</th><th id="col_5">Col. 5</th><th></th></tr>

[code]....