This was spotted in WhatsApp Beta version 2.20.163, which features shortcuts to Rooms in various sections of the app. Specifically, the user can access Facebook’s new feature via the Share menu, as well as in the Calls section of WhatsApp.
Upon clicking the Messenger Rooms icon, the app will present a brief introduction to the feature itself and will prompt the user to launch the Messenger app in order to use it. Not surprising as it is a shortcut to a separate application after all.
The move to eventually incorporate features from other Facebook-owned services in a united ecosystem had been set in motion for a while now. These include the ability to cross-post Instagram Stories to Facebook and vice versa, with future plans to have users from the image sharing platform, Messenger, and WhatsApp to communicate with one another as well. As for the latest WhatsApp Beta mentioned earlier, the update is currently available to a limited number of beta users in a few countries, but it should expand to more countries soon. Also, the new feature is only available to Android users at this time, and is expected to roll out for iOS later on. (Source: WABetaInfo)