enue by:(1) determining the total revenue of each of its members as provided by Section 171.1011 as if the member were an individual taxable entity;(2) adding the total revenues of the members determined under Subdivision (1) together; and(3) subtracting, to the extent included under Section 171.1011(c)(1)(A), (c)(2)(A), or (c)(3), items of total revenue received from a member of the combined g