Formbuilder:Several forms pass values to one checkout form

[Saeglopur]

Hi, I'm using FormBuilder and I have several different packages whose order forms are populated via the Module Interface Field and Products.

Ideally I would like all these packages to connect to a single options page where the items in the previously selected package are selected upon page load, and the user has the option to customize the package further. This new information will then be sent to a final checkout form where the user fills in the info and checks out. How can I do this? Do I need to use a UDT or somehow modify Formbuilder itself?

(Also, I notice the Module Interface Field doesn't give you nearly as much flexibility as just choosing radio or checkboxes from the list, but I have to use the database in Products, so there you go. Any heads-up from people who are good at using the MIF in FormBuilder gets them an extra hug.)