You could create a second entity. For example SelectionHelper.(Reference association to TimeSlot). In the SelectionHelper create an attribute Date.
Create a Dataview for entity SelectionHelper (where the user can fill in the date they need).
Then place a listview (inside the Dataview) which shows a list based on a microflow. In that microflow make sure the listview only shows objects where the given date from the SelectionHelper is the same as the date in the TimeSlot. Or, I'm not really sure what you want, that the given date from the SelectionHelper is in between the Day and EndTime of TimeSlot.