The checkout wizard for eCart 5 has the option to create checkout pages that do not use a payment gateway.
You would need to create separate eCart objects, one for the regular web shop, the other for the franchise products.
basically, you are creating two separate stores. each store will have it own eCart opbject.
each store will have it's own set of files for the product catalog and checkout functionality.
the eCart objects will both be in the same eCart folder, but the files that use them can be anywhere on the server.