Is there a User Hook in the Journal Post Program?

Is there a user hook either in the Journal Import or Journal Post program that would allow users to execute their own code to properly handle many-to-many intracompany balancing? The intercompany segment is currently only being populated for one-to-many and many-to-one journals, and Support claims there is no way to identify the BSV for many-to-many segments. This is not true. By stepping through the net DR and CR values for each BSV, it is relatively easy to determine the amounts that need to be transferred from one BSV to another in much the same way that is done on one-to-many