The thing is that you can't have it both ways i.e. get the benefit of
total operating cost divided by # of members
and at the same time
being able to walk away from unexpected bills
I am familiar with a "group" operating a very classy aeroplane, the like of which is just about impossible to self fly hire, where the hourly rate is extremely competitive, yet the renters (they aren't owners at all) aren't liable for anything. The owner does it just to recoup some of the fixed costs. Obviously he's very fussy about who flies it - a current IR or a working ATP is the minimum, and no way to get airborne solo without a number of check flights and a full understanding of ALL the kit.