What happens when you invite a player through Steam OSS when they're not playing your game?

I’m trying to set up Steam’s invitation interface but I don’t know how it works when players are online but not in the game. When a player is playing the game, you can just use a FOnInviteReceivedDelegate delegate to execute any code you want. But Steam lets you invite friends who are online, but not playing your game. What happens in these cases? Is there a way to make accepting the invitation open the game and execute some sort of code?

Thanks in advance!