ForcePlayerStartLocation

Parameters
whichPlayer player
startLocIndex integer
comment

Forces player to have the specified start loc and marks the start loc as occupied which removes it from consideration for subsequently placed players ( i.e. you can use this to put people in a fixed loc and then use random placement for any unplaced players etc. ).

return type
nothing
Source code
native ForcePlayerStartLocation takes player whichPlayer, integer startLocIndex returns nothing 
Source
map-setup.j
wc3modding.com
ForcePlayerStartLocation