Like Axes and Allies http://www.wargear.net/boards/view/Axes+and+Allies .

Is it possible? If so, how does it work?

I played around a bit with the options. If I select team tournament, Teams per Game options disappear. Same happens on No Teams in Round Robin but for Swiss and Elim, options show up.

Will it be individual tournament with each player being randomly allocated to a different team on each round?

As far as I know, the official tournament system doesn't support asymmetric team games. Thingol has occasionally manually run an AnA tournament, but it requires a lot of cooperation and a huge amount of offline work.

Ok, thanks. I realised my Championship code wouldn't properly display the game format for these type of boards as I do Players per Game/2 v Players per Game/2, since I only allow 2 teams per game in team tournaments. I'd have to fetch the info from the board page which would be a bit of work, but since it's not supported I don't need to change anything.

I guess one way for it to work would be to bench players. For example, in AnA it's 3v2, so teams would be of 3 and then one player would have to be benched when assigned to Axis.