Need to replace all the parts inside the tank of Jacuzzi toilet

The "universal" parts found in Lowe's or Home Depot do not do it for my Jacuzzi toilet. I believe it is the Maxima model. These parts are very different from a standard toilet. For example, instead of just two holes (one for water coming in and one for water going out), there is a 3rd hole, which appears to be a separate overflow drain. In the universals, the overflow is routed through the hole that the flapper covers. Additionally, there is a plastic tank inside the porcelain tank, which is supposed to hold all the water. I can't find anywhere that sells a complete replacement set of parts.