40 ILCS 5/7-224
Notwithstanding any other provisions of this Article, the combined benefits and contributions provided to any participating employee by all plans of any participating municipality and its instrumentalities and any participating instrumentality shall not exceed the limitations specified in Section 415(b), (c), and (e) of the Internal Revenue Code of 1986. If a participating employee's benefits or contributions under this Article, combined with those under any other plan of the participating municipality and its instrumentalities or participating instrumentality, would otherwise violate those limitations, the benefits and contributions under the other plan shall be reduced, rather than the benefits and contributions provided under this Article. To the extent that the other plan fails to limit such benefits and contributions, that plan shall be disqualified.
40 ILCS 5/7-224