Interactive Calendar Tool or Multi-select Date Tool

I am looking for a tool that would allow me to use the date selector as a multiselect option vs a single select.

I have added a screenshot of an interactive calendar that would likely be a step above what I am talking about with the capability of selecting directly from a monthly view of the calendar and the ability to provide messages on the days, pending who may be logged into the application. Any chance this tool already exists and I have just not looked in the right place?

any progress on this subject.