I found a backwards way of doing it.
Code:
<if condition="!is_member_of($bbuserinfo, 1, 2, 3)">
<if condition="$post[postcount] == 1">
$spacer_open
<div style="padding:0px 0px $stylevar[cellpadding]px 0px">
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
<td class="thead" align="left">Sponsored Links</td>
</tr>
<tr>
<td class="alt1" align="center">
ADSENSE CODE
</td>
</tr>
</table>
</div>
$spacer_close
</if>
</if>
Unfortunately I have to use this code three times (post count for 1st, 5th and 10th) . I have to change the post count for each copy of it.
I wish I knew a way to add the other post count numbers into the first conditional.
Any Ideas?