InfoPath Dev

I have two Sharepoint Services LIsts being populated through a Infopath 2007 form. Both forms produce a ID code however I would like one of the ID codes automatically populate to the second list.

I've attached both lists. "List 1" has the unique ID while "List 2" has it's own unique ID too. However I would like "List 2" to have the newest ID from "List 1" get populate on the newest line on "List 2". I do not want to use a lookup drop down box.

Hopefully this makes sense.

I wonder if you could use a data connection to list 1 and use the max function to get the highest ID from list 1? You could use a rule to set the field in list 2 to the max from list 1.... You just want to be careful when you have this rule, since if you query list 1 on load, someone could add an item while you are working in list 2 - so generally, you'd want to query and set the field right before you submit the form to list 2.