Need user to fetch data to update form using iframes??

Need user to fetch data to update form using iframes??

Hello,

I have 2 stateless forms, each called to an iframe in an HTML view.  On the bottom iframe is a duplicate of my main form (which is public) used for updating records.  The top iframe has two single line text fields, Group ID and Listing ID.  I want to use these fields to look up a record and populate the bottom stateless form so users can update that record.  Our organization has 1000+ groups whose officers change all the time, so Zoho user accounts are not going to work here.  I want whoever is designated by the group, if they know the two ID numbers, to be able to update that group's listing.

I need help to do this because it isn't anywhere that I have found.  I know how to lookup and populate a stateless form on the same page, but I don't know how to do it by getting the data from one iframe to the other.

I hope this makes sense,
Thanks