Is it proper to to add 's only to the last entry in a list as in the example below:
Dad, Jeff, and Nate's steak was cooked to perfection.
Or should it be:
Dad's, Jeff's, and Nate's steak was cooked to perfection.
If they are seen as a group, I inflect only the last noun for genitive case with the aid of the saxon genitive.
Tom and Mary's cat died from carbon monoxide poisoning.
This probably means that their cat died, but it could possibly mean that Tom, as well as Mary's cat, died. So one has to change the sentence to remove the ambiguity.
One would be inclined to say "Tom's and Mary's cat died from....." But this apparently is not allowed; it's against the rule for joint possession. So one apparently has to say 'The cat belonging to Tom and Mary died from.......'