For every 2 people on a team there is one 'Jug'.
If you kill an enemy 'Jug' and your not already a 'Jug' you become a 'Jug' for your team.
If killed you can still re-spawn as long as there's still a 'Jug' on your team.
If all the 'Jugs' on one team are dead then the opposition has to clear up the rest of them, still protecting their on 'Jugs'. But if one of the (now) hunted teams kills on of the opposition, then therefore they are now a 'Jug' and the deceased part of their team are entitled to re-spawn.