[profitbaron]

I don't know exactly how YCNYC worked (so this may of already happened) but my suggestion would be to do seperate groups i.e. Group 1 & Group 2 and then in the Evening you could bring together as an "After-Party" type thing to facilitate networking etc.

For instance if you were to speak as well as some of the YC Alumni then the following could happen;

Group 1 - YC Alumni - BREAK - PG

Group 2 - PG - BREAK - YC Alumni

Obviously this would add a few extra problems, including increased costs although, this could easily be solved having a small fee for attendance (again I don't know the exact details of how YCNYC worked so if it was a free meetup charging $10 say wouldn't bother people and would help to recoup the additional costs etc)

This would make the event appear much smaller than what it actually is thus, making it more informal as well as allowing, people to network in the Evening as well.