CSS Question: Need to show this while hiding others with the same parent class

i want to show this using css

<code><div class="control-group custom "><label for="ticket[selections]" title="selections">Selections:</label><div class="controls"><select id="ticket_selections" name="ticket[selections]"><option value=""></option>
<option value="office">office</option>
<option value="pool">pool</option>
<option value="party">party</option>
<option value="Meeting">Meeting</option>
<option value="Miscellaneous">Miscellaneous</option>
<option value="Projects">Projects</option></select></div></div>

and hide the other control-group custom's that don't match this....


What would the css look like?

 

<code> just a reference for displaying code -- may not be needed on this site.