Group tournament game generation

gistfile1.txt

Keep first position while rotating rest of array

[home teams]
1,2
3,4
[away teams]

1,3
4,2

1,4
2,3

If teams should meet more than once switch home and away sides

[home teams]
4,3
2,1
[away teams]

2,4
3,1

3,2
4,1

I reverse the array and hold the last element but it is probably more logical to simply 
switch which side is home or away now that I look at it.