I am not a real estate attorney but I have seen this on the appraisal side of things. As always, consult with your probate attorney to make sure everything is done properly.
The easy way is to have each of the 5 siblings sign a quit claim deed to transfer their personal ownership rights.
If the 5 siblings expect to be paid for their share, well then that is a slightly more complicated matter. To accurately determine the value of each share, you cannot simply take the market value and divide by 6. This does not account for the loss in value that comes from having 5 other people to negotiate with every time a decision about the property must be made. Multiple ownership reduces the rights of each owner and thus affects the price of the property. You should pay for an appraisal which is done by an experienced appraiser.