Pvt Ltd Company entering in another association of persons

 Actually I am a customer of  private Limited company, an association of persons formed by 9 individual private limited companies and 4 individual persons-total 13.
The private limited company have legally acquired constructed and selling flats in a housing complex.
 My housing loan bank is asking for individual copy of resolution which must be taken by each of these 9 pvt ltd companies in order to be a part of another association of persons
  My question is-
    1. Is this absolutely necessary to have a resolution taken by the board for a private limited company to enter into another association of persons?
    2. If they produce- association of persons certificate, memorandum of understanding. will these two be sufficient proof that the association of persons formed by those 9 pvt ltd companies and 4 individual persons are legally valid and viable?