Yes you can play with your own group. To be able to have a team of players made up of only your own group you will need to bring 20+ players with your booking. To be able to play with an exclusive group that has their own game zones on the day, then (depending on the rules of that particular centre) you will need to bring along 40+ players with your booking.
Note: final groups and teams are decided by the centre managers or marshals on the day. Nationwide Paintball takes no responsibility to changes made in teams for the safety of other players involved in the game day.