Of course a man can't support 5 sister-wives

But, that isn't an issue, as all woman are being supported by all the men.
(its either that, or let them all die)

The notion of one man supporting "his" woman are over.
It is already all the men, supporting all the women, and most not getting anything for it.
Now, we just have to realize that, and then choose a better, more equal way of supporting them.