Use a skill for that. For example: enemys.skill70 = 1, Platforms = 2, Items = 3 and so on. Now in your event you can read the you.skill70 from the Entity that make the collision with your Player. You can use the following code:

if(!you) {return;} // collision with blocks...
switch(you.skill70)
{
case 1: collision_enemy_func(); break;
case 2: collision_platform_func(); break;
case 3: collision_item_func(); break;
}