each sibling an equall pot of family $$$ to use. They can also use their own real $$$ to buy.
Then auction the properties to the highest family bidder until they are all sold or you gave some nobody wants. Sell those to the public.
Use quit claim deeds to transfer titles to family members and have the ones buying pay any closing costs which will be minimal. They get a bargain, but will eventually sell it or their heirs will and then they will have selling costs.
If some properties are sold to the public, any gain or loss vs pot value for that property would be shared equally
Thank me later.