Developing multiplayer games is difficult, even though Construct's Multiplayer object takes care of many of the complexities for you. In the same way the events...
Is there way to get all rooms present on server?
yes there's an action to get a list of all rooms on the server, for your game.
"request room list"
then use an event:
"on room list"
This is not supported as it would list rooms from dozens of other games unrelated to yours.