Whether PF deduction is Mandatory for Societies

Whether Provident Fund dedcuction is mandatory for Society registered under Tamilnadu Societies Reg Act, and has its units at various location at tamilnadu having activities such as Schools, Boarding and Charitable Activities. Society is presently deducting PF for the employees employed in School. The Officer from PF dept required to deduct PF for the temporary staffs employed in Boarding. Only 2 staffs employed in Boarding and rest of the staffs are members of the Society (Sisters). In such circumstances whether PF should be deducted.