Subforms and scheduler

Hi

I have two forms, Form A and Form B.

Form A contains the details of a product and Form B as a subform.
Form B contains the name and email address of a person and a date.

I want to run a scheduled job which 3 weeks after the date on form B emails the person on form B. However, the email must contain the relevant product information from Form A. The problem I have is getting the relevant information from Form A.

Additional information: Form B permits duplicate entries ie a person's details may be present 2+ times (this is need) in the Form B database with each instance being set against a different product.

I would really appreciate any support you can provide.

Thanks