Assuming you "each" received a separate 1099-S, if the property was deeded to you by the previous owner before that owner died, then your cost basis is that original owner's cost basis, plus the cost of any property improvements done after the original owner before you, purchased it.
So for each of you, assuming your individual 1099-S's report your individual share of the proceeds, your cost basis will be 1/5 for each of you. You'll be reporting actual numbers on the tax return, of which it is rare for any of those numbers to "agree" with the 1099-S. The 1099-S only shows the cash you received at the closing. That does not mean that all of that cash is taxable, or that the cash received is the "only" taxable portion of the sale.
So you'll report your 5th of everything on your tax return, "as if" you never received a 1099-S. If you keep looking for something asking you for any amounts reported on the 1099-S, you'll go crazy because you'll never find it.
