Campaign Responses / Marketing Lists

We have an area of the business that generates campaigns outside of Dynamics but also want to record their information in Dynamics as well *sigh* - we created the campaign and then manually recorded the campaign responses on who attended and event.

Once all the responses have been recorded I want to add all the people that responded to a marketing list but  I can't seem to find anyway to associate the responses activities to a marketing list in any way.

Is this at all possible?

Thanks