Create an 'Event' (Opportunity?) where multiple accounts can be tracked

Hi,

I would like to create an event, or opportunity in CRM where I can associate multiple accounts to this opportunity.  For example, we have a conference in India where hundreds of our current Accounts will be in attendance.  I would like to be able to easily track these accounts to this event and easily associate this event (opportunity) with all of these accounts.  Since there are hundreds of accounts at this event, it would be cumbersome to create 100 opportunities with 100 customers. 

Can I do this with 'Relationships'?  If so, i need some assistance.

Thanks in advance.