Team Groups A vs B, A cannot use Group 1, must choose from Group 2 & 3.
A vs B, B can use any team from Group 1, 2 & 3.
A vs C, A cannot use Group 1 or 2, must choose from Group 3. A vs C, C can use any team from Group 1, 2 & 3.
A vs A, it's a free for all, any team available.
B vs C, B cannot use Group 1, must choose from Group 2 & 3. B vs C, C can use any team from Group 1, 2 & 3.
B vs B, it's a free for all, any team available.
C vs C, it's a free for all