GST on electricity charges recovered

XYZ is a commercial Cooperative Society & has one electricity connection and hence one bill from BEST for the whole building. Individual members having sub meters only to assess their reading. Every month society is taking the actual reading from members sub meter for actual consumption of the electricity. Based on the same, electricity charges are recovered from the members. Is XYZ liable to pay GST on the electricity charges recovered from members even though it is only a reimbursement?