extend groups to conditional groups

[sharkiteuthis]

conditional groups:

• play 2 of X Y Z iff X or Y or Z is in the lineup
• play all of X Y Z if any is in the lineup
• play none of X Y Z if A is in the lineup
• play 1-2 of X Y Z is A is in the lineup

[BenBrostoff]

This remains a feature I'd really like to see FWIW. For NFL this season, would've used it a ton to say for TB to say if Chris Godwin is going to be in a lineup, don't play Mike Evans. For stacking I think this is a good one - if you know two players are inversely correlated, you'll want a conditional group like above. @sharkiteuthis you think you know how to implement this? I have some ideas but not sure if they'll work.