Divine Multiclassing and Prestige Classes
For every divine rank you gain. (1-19) You gain a Gestalt level in another class or Prestige class.
You select a single class or Prestige class. You can take standard classes as you will however. Prestige classes must be completed before you can select another. In such a case select another. In all classes you gain all of the abilities of the new class level normally. This effectively treats 20th level as a hard limit for divine class level, but not as a hard limit for total character level.
Added benefit; your worshipers can gain the knowledge you know from the Prestige Classes and mortals who worship you can now train.