[Zope] Single form, multiple classes

I am trying to dig a little deeper into Zope's capabilities and have created sample multiple classes to handle company, account, contract and billing information, for example. Since you could have multiple accounts for one company and multiple contracts per account and so on. How can I use one entry form to handle parsing the data to multile DB files? Is this something that can done in DTML or will I have write a python script? The example I'm playing with is as follows: CompanyInfo class AccountInfo class ContractInfo class BillingInfo class -- Michael Lewis "The early bird may get the worm--- but the second mouse gets the cheese"