Surprised no one has mentioned this...

2x Citi AA cards. Offer is 50k right now. So two cards would get you 100k. Each first class ticket is 75k. One ticket right there.

If each of your 4 people could do that, everyone flies first class.

The spending requirement is a little rough... but who knows how much spending you do? (you didn't tell us)

EDIT: Hey look at that, you did tell us. It's doable in your spend level, depending on how quickly you need the miles.