I think it is possible but for something like that you may not want to use Game Mode. Game Mode should be reserved for rules and such, for the game. Perhaps player state would be a better location. Also keep in mind how your game is developed, ie multiplayer game or single player. Certain blueprints like Game Mode, Game State and Player State are replicated so there may be some functions you don't want or need to have replicated to the server or other clients.
Most actors have a "Is Visible" and "Hidden In Game" boolean default setting so all you need to do is get a reference to the actor you wish to"toggle" then set appropriate boolean.
Hope this helps! Thanks!
kissanime