Formidable Forms: Ordering input options by multiple columns, not rows

custom.html

<div id="frm_field_[id]_container" class="frm_form_field form-field [required_class][error_class]">
    <label  class="frm_primary_label">[field_name]
        <span class="frm_required">[required_label]</span>
    </label>
    <div class="frm_opt_container">    
<div style="float:left;padding-right:80px;">[input opt=1][input opt=2][input opt=3][input opt=4][input opt=5][input opt=6]</div>
<div style="float:left;padding-right:80px;">[input opt=7][input opt=8][input opt=9][input opt=10][input opt=11][input opt=12]</div>
<div style="float:left;">[input opt=13][input opt=14][input opt=15][input opt=16][input opt=17][input opt=18]</div>
</div>
    [if description]<div class="frm_description">[description]</div>[/if description]
    [if error]<div class="frm_error">[error]</div>[/if error]
</div>