Hi!
This may require some custom coding in my opinion – all because of the multidate picker. That is a very complex field and I’m not sure if it’s possible to simply filter based on it’s value, as it’s not a single date, but likely an array of date fields.
However, I believe it is very likely possible to create a radio button or even a checkbox type of filter to choose to show between All/Working Today values.
Can you please add temporary FTP and back-end access? I will have to take a direct look at this, as I don’t know how the multidate picker stores the values. Based on the exact setup I will try to suggest a custom code snippet, which would convert the All/Working Today checkbox/radio filter to an actual results filter in the post processing based on the user selection.