Use a different layout on these pages. You can probably do this by using a setting (plugins.tx_yourext.settings.layoutName = Layout2.html
), and then using that in the template:
<f:layout name="{settings.layoutName}"/>
The layout on the special pages renders the section, the usual layout does not render it.
EDIT: You could also just use a condition in the layout. Set plugins.tx_yourext.settings.showProductSearch = 1
(or 0) on the pages, preferrably using a TypoScript constant. Then use it in a condition:
<f:if condition="{settings.showProductSearch}">
<f:render section="Productsearch"/>
</f:if>