it's kinda simple.
When u go into triggering
Do somethingl like this
Example
Event: Unit enters ( your region)
Condition: Boolen ( Entering unit is a hero equal to true
Action:Now as ur first action i would say u make a varible of type unit and named " player 1 hero " like that.'
Set Player 1 hero to Entering unit
Then Wait 0.01 seconds as next action.
Make a action : Store Player 1 hero in game cache named ( ) in ( ) named ( ) like that and now REMEMBER those named , in and named
.
Wait 0.01 Seconds
Unit , Remove Player 1 hero from the game
there now it will be saved into a file on the players computer
in next map just enter another region and insted of store u load the unit from same folder and names and in that file.
Hope this will help ^^