[LifesGreatestGift]

does this work?

<vb:if condition="$position == 2">DO THIS</vb:if>

only way you would be able to tell, is if you are the author of the second thread (or whatever number you put in the conditional). Test it out. If it doesnt work, in the code I gave you

FIND

    vB_Template::preRegister('SHOWTHREAD',array('display' => $display));

REPLACE WITH

    vB_Template::preRegister('SHOWTHREAD',array('display' => $display));
    vB_Template::preRegister('SHOWTHREAD',array('position' => $position));

Then see if the conditional works.