- Generating random maps in Heroes of Might and Magic III: The Shadow of Death.

Is there a pattern to half of them being available? Perhaps only warriors or only mages are available? And how did you determine availability? In the game (I don't know about HOTA), only up to 8 heroes can be active on the map; the rest can only sit "hidden" in the garrisons of cities.
Please provide/show the names of the heroes available to you in any way that is convenient for you (words, screenshots, video).