Hey Charles

It should be possible via Exact Targets API, though it would require some heavy coding.

There might be a alternative though. You could try merging a Exact Target form with a Unbounce form. I can’t guarantee it will work but it might be worth looking into.  Unfortunately I don’t have a exact guide on how to do this, but I do have something that would help. I wrote up a community post detailing how to connect a custom Salesforce form to your Unbounce form. The process is generally the same so if you have the technical chops you should be able to get it working similarly. The process is pretty much re-creating those fields using Unbounce tools.

https://getsatisfaction.com/unbounce/topics/how_do_i_assign_my_leads_to_a_specific_campaign_in_salesforce_custom_salesforce_integration

Hope you find this helpful. If not hopefully another customer can chime in with a better solution