You cannot do this, basically.
You can only indicate that the type is the entry point, and not the main overload inside the type should be the entry point.
You can create a nested class containing one of them if you want to save the code in the same external type:
using System;
using System.IO;
using System.Text.RegularExpressions;
class Test
{
class Parameterless
{
static void Main()
{
}
}
static void Main(string[] args){}
}
/main:Test, /main:Test.Parameterless , , Visual Studio.