e-commerce, customizing checkout process based on product

After lots of research, I'm considering using Wordpress and either the WP e-commerce plugin or the Shopp plugin. We'll also integrate with PayPal to do the actual credit card transaction.

The products that we will be selling will be a combination of regular products and "odd" products that have crazy dimensions an开发者_开发问答d weights. Whenever one of these "odd" products are part of the shopping cart, we want the transaction to be passed on to a sales associate. The sales associate will look at the order and provide estimated shipping information (they need to figure out how to group and package odd products with regular products, if possible).

Will the two plugins that I mentioned allow you to intercept the checkout process to do this?

Is this something that ecommerce plugins/engines allow you to do?

I'm thinking of just tagging these "odd" products and then I would hopefully be able to "hook" into the process somewhere.

I've also crossposted this at the wordpress stackexchange.

I have used WP E-commerce in the past. It allows you to create an "odd" product and define a different landing page instead of the paypal's without too much trouble. You will have to write your own procedures on such landing page, to handle the user's information passed by the WP ecommerce's script, though.