Adding a Civ to my map

Hello all. I've searched for this topic and found similar posts, but they have no resolution.

I have made a map of SE Asia and Australia on the Builder and would like for civilizations to randomly start in specific squares on my map, however I cannot make this happen. For instance, I have selected roughly 30 spots on my map where I would like a civilization to randomly start (in Java, Borneo, Luzon, Cambodia, Eastern Australia, etc.) however when I play the game, my civilization only starts in a few spots on the largest landmasses (Australia and Indochina), never in the East Indies, Philippines, New Guinea or New Zealand.

Is there a way to make sure I can select any civ and have it randomly start in any of the predetermined starting cells? Is this even possible?

Why is something like this that is seemingly simple so complicated to accomplish?

If there is a link where this issue is addressed and resolved, please point me in the right direction.

Moderator Action: Welcome to Civfanatics! The "Modding Tutorials and Reference" sub-forum is for completed tutorials and reference guides only. Any requests for help, queries and works-in-progress should go in the main Creation and Customisation forum. I've moved this thread there.
Please read the forum rules: http://forums.civfanatics.com/showthread.php?t=422889

You need to start the game through the Mods menu (even if you don't use any mods), and check "load scenario" on the setup screen.

Why is something like this that is seemingly simple so complicated to accomplish?

Click to expand...

Because the devs made it so.