There are no direct flights to Dublin from down under. The only one stop option from either Sydney, Melbourne, Brisbane or Perth is with Emirates and Aer Lingus via Dubai. These two airlines recently came to a codeshare agreement and combine to issue one ticket and can often provide the cheapest fare in addition to the fastest connection (and you avoid Heathrow). These fares cannot be booked on either airlines website but companies such as STA or Trailfinders usually have excellent deals.

Other good options are usually via London, Frankfurt, Paris or Amsterdam with either British Airways, Singapore Airlines, Cathay Pacific, Air France, Malaysian Airlines or Virgin Atlantic.

The best option is to negotiate a group deal directly with the airline. Usual practice is to offer a discount of 5-10% for groups, depending on the size.