Cleaning up mineral rights ownership

What is the best way to clear up small ownership issues? Our problem- There are four grown adults (some with kids) and they are to share and share alike and they all agree that that is the goal. However, due to some poor legal advice back in the 50’s, 60’s and 80’s there is a small decimal difference between the four. All parties agree to share 25% of whatever is produced and wish to insure that their kids get the benefit through rights of inheritance. All of the principals are long dead, so how do we clear this mess up and not screw it up any worse? Yes, hire an attorney, but whom? Do we file a cross conveyance?

HELP!

DM's advice is sound, assuming that the four adults actually hold record title to the mineral interests. You want to make sure that the four persons have clear record title to whatever percentage of interest that they hold before recording another document that could, potentially, cloud title to the property. A good landman can conduct a record title search for you if one is necessary.