One idea that I came up with is that each vehicle (also gas bill) has a total of a certain number of points based on contents. For example, my vehicle would have 5 points. One each for me, Melissa and Joe ... one for my bike .... one for Ruben's bike.
Based on that, I would pay 2 points (me and my bike), Joe would pay 2 points to me (him & Melissa) plus one point to George for his bike. Ruben would pay 1 point to me for his bike.
For George's truck, he has a total of 8 points (5 bikes, 3 people). Each person riding pays a point for themselves and an additional point for the bike being hauled. Those riding in other vehicles pay one point for the bike being hauled.
Ruben/Ever - figure it out between yourselves, pay the point for bikes being hauled.
Robert/Robert - on their own, but Robert still pays the point for the bike being hauled.
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Based on the above, that's $102/point on George's transport ... $70/point on mine. If anybody has a better way of figuring this out, post it up. It's time to pay off the credit card.
OK, We're going to roll with it. Basically, everyone that went probably owe's SOMEBODY SOMETHING. I'll try to break it all down with $$$ going to Big George (G2) or myself. This is NOT legally binding as I may miss someone or a bike. You know if you went and if your spouse/bike did. 
... others are still due. 
Please get the money together and paid to the appropriate person.