当至少有许多人需要该产品时，Magento会出售

I am trying to make this option to my magento store. People will go into the store and they will have to show interest for a product. When the number of interests reach 5 for example the product can be sold.

I will have to create a view2.phtml for this and add custom layout to a category so I can choose in which products I need this option. But how can this be done? Is there any plugin or way to achieve?

Thank you

You can add Custom Layout Updates (Product->Design) for each product. By adding a rule like

<reference name="product.info">
    <action method="setTemplate"> 
    <template>catalog/product/view2.phtml</template></action>
</reference>

the product page will be view2.phtml just for that single product.

Note that it is better to place this new file (view2.phtml) inside your own theme folder instead of using the base directory.