In an open work environment, it is sometimes difficult to focus. Put on noise-canceling headphones for times when you are working on a task that requires concentration. Earphones serve as a visual cue to your colleagues so they do not bother you unless absolutely necessary.
Have a common "code" that symbolizes the unavailability.
Example:
By accepting you will be accessing a service provided by a third-party external to https://solutionsandco.com/