[Zope] newbie application design question

[Chris Snow]

I would like to create a basic application using Zope. Some of the 
functionality I need to build is as follows:

- input person details (using formulator form 'form_person')
- input product purchased details (using formulator form 'form_prod')
- input payment details (using formulator form 'form_payment')
- write all details to mysql (using BDB tables) within one transaction, i.e.

    begin
      insert into person ...
      insert into product_purchase ...
      insert into payment ...
    commit

How can I maintain persistence of the data collected in the three separate 
forms and then save the data to the database in the one transaction?

Any help would be appreciated.  

Thanks in advance,
Chris Snow

PS. My knowledge of Zope so far is from reading the excellent Zope Book.