Limitation on number of tickets per registrant

We are using Constant Contact to register attendees for a retreat weekend.  We need contact information and certain details (such as food allergies) for each individual coming to the event.  The current setup allows one person to register for a group of attendees by asking for multiple tickets (i.e. multiple people).  When this happens the only contact information collected is for the one doing the registration on behalf of the group.  We need each individual coming to register separately so we can collect the necessary information to properly prepare for our event.  Is there a way to limit registration to one ticket per registrant so it will force each individual to register separately, thus submitting their individual information?