Dynamically load level locators file (or any P3D file)

Hello SHAR modding community!

I'm trying to load different level1 locator files (copies of 'art/missions/level01/level.p3d') based on a certain condition.
In example:

CustomFiles.ini

[PathHandlers]
art\\missions\\level01\\level.p3d=Resources/level01/level01.lua

level01.lua

if SomeChoice == 1 then
    Game.LoadP3DFile("\\Mods\\" .. GetModName() .. "\\Resources\\level01\\custom.p3d");
else
    Game.LoadP3DFile("art\\missions\\level01\\level.p3d");
end

The game crashes on level load, with a ton of similar messages:

• Locator type 3 'level1_carstart' not found for 'InitLevelPlayerVehicle' command
  
• A crash occurred in the following script: scripts\missions\level01\leveli.mfk (line 5); Script command InitLevelPlayerVehicle, Arg list famil_v, level1_carstart, DEFAULT

The 'custom.p3d' is an exact copy of the original file (for now). I don't understand why it can't find the locator types.

I'm having some trouble understanding how it all works. I'm new to SHAR modding, but I'm quite, if I can say, an experienced programmer.
If anyone can give me an explanation or can point me to a more in-depth documentation or discussion on this topic.
Thanks

Yh the game isnt going to be able to find a file outside of custom files like that. Open and output the file with lua

Output(Readfile(GetModPath() .. "/Resources/level01/custom.p3d))

I see. Thank you for pointing me to the correct function.

No need to even read the file. You can use Redirect function to make the game read another file. Like this:

if SomeChoice == 1 then
    Redirect(GetModPath() .. "/Resources/level01/custom.p3d")
end

If SomeChoice is 0 the game will load original file.