I'm building an application where each order must contain exactly one product from certain "base" prodcut categories followed by none-or-more optional products. Imagine booking a holiday where you must have exactly one flight and exactly one hotel plus a number of other optional add-ons.
Because there are a small number of base products (i.e. filght and accomodation in the example), I'd like to have a drop-down list for each of those, and then use the normal mechanism to search and add any other add-on products.
I don't have a lot of experience customizing forms to this level. How can I go about implementing this? or is it just too complicated and I should stick to the standard method of adding products to orders?
Thanks