If you are an Organization Admin, you can join any room created by a colleague from your organization, without an invite. You will be added to the Host Team and inherit all of the Host Team's permissions.
How do I join a room created by a colleague in my organization?
After logging in to ProDeal, click on the new tab on your dashboard called "Organization Rooms."
Click on the blue box labeled "Join Room" on the right side of your dashboard.
Confirm joining the room by clicking the blue box labeled "Join Room."
Your newly joined room will be listed in the Rooms tab on the dashboard as well.
The Rooms tab under the Organization Dashboard will only list rooms created and hosted by other organizations that users of your organization have access to.