Modify Excel Multithreading

Excel (2007+) is fully capable of multi-threaded calculation. However, multi-threaded calculation is, somehow, triggered off if Excel detects a circular reference. I need some modification to the excel program (or otherwise) which, somehow, gets around this trigger and forces excel to perform multi-threaded calculations even if there are circular references in the workbook. The solution should, somehow, allow me to use excel with and without this modification (whether by using 2 builds of excel or, better, inserting a button to toggle this behavior on and off). I do not know if this is possible without MS source code, but respond if you know how to resolve this problem.