fly73 - it is basically parlaying 2 of those teams together for every combination (kind of like a "box" in horse racing). For instance ... if you put $20 (as your notional bet, meaning $20 for every 2x parlay), you would be risking $200 to get every possibility (in order to win $573).
Lets say the Mets lose and you hit the other 4 ... you would win $260
Lets say the Mets and Jays lose, but you hit the other 3 ... you would win $38
If you lose 3 of those teams, you would lose some money, but not the entire $200
Lets say the Mets, Jays and the over loses ... you would lose $122
Hope that makes sense. Here is a calculator to figure it out as well:
http://www.casinoreview.org/resources/caculator/round-robin-calculator/