Sub forum specific header modifications

[oldgoat]

Hello to all
I have modified the following code ? see below: essentially what this does is display a specific ad in the right side portion of the header. The left side will always have the same banner in place. I am looking for suggestions to accomplish the following:

1- is there a way to include a range of forum id?s in an array, instead of entering each value individually. (example below)
<if condition="in_array($GLOBALS['forumid'], array(18,19,20,25,26))">

2- if a forum id is not included in the array, can a default image be displayed
3- how can I add left / right columns and custom header to the www.website.com/forum/index.php? page only, all other pages are to be excluded. (I assume that all modifications will be made to the header / footer templates) this page in running vbadvanced 2.1.0

thank you in advance for all your help

PHP Code:

<!-- logo -->
<a name="top"></a>
<table border="0" width="$stylevar[outertablewidth]" cellpadding="0" cellspacing="0" align="center">
<tr>
    <td align="left"><a href="$vboptions[forumhome].php$session[sessionurl_q]"><a href="http://www.website/forum/index.php?">
<img src="$stylevar[imgdir_misc]/BANNER.jpg" WIDTH="410" HEIGHT="100" alt="banner" border="1"></a></a></td>

<!-- FORUM SPECIFIC AD MODIFICATION -->

<if condition="in_array($GLOBALS['forumid'], array(18,19,20,25,26))">

</if>
<if condition="in_array($GLOBALS['forumid'], array(25))">
        <td align="center"><a href="$vboptions[forumhome].php$session[sessionurl_q]"><a href="http://www.hyperlink.com">
<img src="$stylevar[imgdir_misc]/AD.jpg" WIDTH="570" HEIGHT="100" alt="AD" border="1"></a></a></td>
    </td>
</if>

</if>
<if condition="in_array($GLOBALS['forumid'], array(18))">
        <td align="center"><a href="$vboptions[forumhome].php$session[sessionurl_q]"><a href="http://www.hyperlink2.com">
<img src="$stylevar[imgdir_misc]/AD2.jpg" WIDTH="570" HEIGHT="100" alt="AD2" border="1"></a></a></td>
    </td>
</if>

</if>
<if condition="in_array($GLOBALS['forumid'], array(26))">
        <td align="center"><a href="$vboptions[forumhome].php$session[sessionurl_q]"><a href="http://www.hyperlink3.com">
<img src="$stylevar[imgdir_misc]/AD3.jpg" WIDTH="570" HEIGHT="100" alt="AD3" border="1"></a></a></td>
    </td>
</if>


<if condition="in_array($GLOBALS['forumid'], array(18,19,20,25,26))">
    </tr>
    </table>
</if>

<!-- /FORUM SPECIFIC LINK MODIFICATION -->

</tr>
</table>
<!-- /logo -->

<!-- content table -->
$spacer_open

$_phpinclude_output