You can only apply and participate in one match of your choice. You will need "Deed of Gladiator" and certain amount of participation fee is required.

The "Deed of Gladiator" is 1200 merit points and it is sold from the king of each kingdom. (You can trade but cannot be sold.)

The party leader can apply for the group tournament. Party leader should select the members to participate the event. Be aware, that individual tournament participants may not join the group tournament again.
You can view registered party members by clicking the party leader in the list. Maximum number of the party is 7 players (including the party leader)

Party leaders can remove and add party members only during the Group recruitment is in progress.