Host/Join Multiplayer

Now i want to try to take this further and i have been working on it since my last post but i need some help. I want some way for this system to detect if the ip typed is hosting a game or not. Will i be able to do this with Booleans. For example, I type in a ip that is not hosting a game and a message pops up telling me so. I have most of this setup but i cannot figure out how to cast between widgets. I tried putting a bool in the “host” button event and having it set to true that changes a branch in the join blueprint to allow to play to join. But that doesn’t seem to work. How can i make the bool change from False to True when a game is being hosted on that ip?.