The plural possessive form is hamsters'.
Singular possessive: secretary's Plural: secretaries Plural possessive: secretaries'
The plural is relatives. The plural possessive is relatives'.
The plural is lads. The plural possessive is lads'.
The possessive form of the hamster belonging to my sister is "my sister's hamster".
The plural form is echoes. The plural possessive is echoes'.
The plural form is suffixes. The plural possessive is suffixes'.
The plural form is Mexicans. The plural possessive is Mexicans'.
The plural form is stepsisters. The plural possessive is stepsisters'.
The plural form is inches. The plural possessive is inches'.
Something belonging to more than one hamster would be written as hamsters'. So, "We looked into the hamsters' cage at the pet shop."
The plural possessive of "Father" is, "Fathers"
The plural possessive of bandit is bandits'.