Is there anything more annoying than the -‘s? (Well, other than tornadoes.) When do you use -‘s and when do you use -ies? Even worse, what about -ies’?
It all comes down to possessive or plural.
–If something is being owned, it’s -‘s: The family’s car. (The family owns the car.)
–If something is more than one, it’s -ies: The families are vacationing. (More than one family.)
–If both: The families’ cars. (More than one family, and they own the cars.)
So, ask yourself the question: Does anyone own anything? If not, no apostrophe.