Can I have 1 button to submit multiple forms?

What I need to do is set up an online registration form where a family that is doing the registering can register 1, or several, children. I was thinking that the first form I create would be for the registering family, along with the information for the first child they are registering. I would then make a 2nd form that just asks for a child’s information. I could then place that form on the page as many times as needed, but I need both(all) forms to be submitted with one button. Is that possible? Does anybody know of a better approach to this?

http://wordpress.org/extend/plugins/si-contact-form/