determining which form is posted when press enter key

I have two forms on my JSP page. One is a little search box that looks up a bunch of address book IDs that can be used to load a recipient's info on the page, and so far, the only way I've been able to get the user to be able to submit it is to include a specific Search button for that little search box--otherwise, the other form on the page gets submitted.
To clarify, the page displays a recipients and his/her address, and when you have all the info on the page, you can choose to use that address (submitting the main form). Otherwise, you use the small search box to search for the IDs of address book records you already have, and I'd love to make it possible for the user to be able to type an ID in there and be able to just hit Enter instead of clicking on the submit button (however, I'd probably prefer to use Enter to submit the other form if the cursor is outside of that search box form).
Thanks for any help...

The following code does what you expect. It takes you to google if you press enter while in the first textbox, but javaranch if you press enter while in the second textbox.