(a) Subject to any agreement with security holders, a tax increment district may be created, the boundaries of which overlap one or more existing tax increment districts. Districts created on the same date, however, may not have overlapping boundaries.
(b) If the boundaries of two or more tax increment districts overlap, in determining how positive tax increments generated by that area which is within two or more districts are allocated among the districts, but for no other purpose, the aggregate value of the taxable property in the area as equalized by the Department of Revenue in any year as to each earlier created district is deemed to be that portion of the tax increment base of the district next created which is attributable to such overlapped area.