There is a workaround however.
If you put $x into a variable within the for loop, the executed script can use that variable.
for $x in group["tiles"] do
$var2 = $x;
execute_script("script_2");
end;
If script 2 prints $var2, it will contain what $x was.
The only issue now, is it prints a duplicate of the last item.
So if your group has 3 tiles for example, you get:
Tile 3
Tile 3
Tile 3
as a result.