Lol, I just thought of something that could make the heroes not there. But it will require placing dummy heroes in the game >.<. It'll be messy so I don't think that you want to do what i'm thinking.
Make a dummy HERO with no icon picture, create about 10 of them for each player that you "don't want to see the heroes". Kill the created heroes after 5 seconds or something. The left side of the screen will be overflowed with almost blank spaces (the dead hp bars will still be there >.<) then, when you make a hero, it should be off the screen so you can't click the icon.