Conference Registration Plugin for Wordpress

I have someone who wants be to develop a conference registration for them using wordpress. I have looked and looked at tons of plugins and still can’t find a conclusive answer to my question. The conference registration has to allow someone to register multiple people in the same web session, but each person will more than likely register for different sessions that are available to attend at the conference. Need to save each person’s preferences for the conference and then allow them to pay for all of their people at once thru paypal. They also want to be able to export all of the data in excel format. I’m wringing my hands as I don’t think all of this is possible with a simple freebie plugin. Can someone please tell me if there is such a plugin and if so if it’s reliable? Last year we used “Pinnacle Cart” and it worked great except it wouldn’t handle multiple registrants in one transaction. HELP!!!