I'm thinking this might be possible by creating a calculated field based on the values in Worksheet A that returns either True/False or similar. Then use that calculated field as a filter on Worksheet B. The trick will be getting the calculation to to work correctly, but without more information (e.g. where do the StartDate and EndDate values come from?) I'm not sure what would be needed. I'm thinking that it might need to be based on level of detail expressions. If you could attach a packaged workbook with some sample data it would be helpful in determining how this might be done.
I have the same question. I think this could be done with a URL filter, but other than that I don't know. This seems like a pretty basic use case, but I don't see any clean way for Tableau to handle it. I don't like the URL idea because I don't want to launch a separate dashboard, I want to see the two worksheets in the same dashboard. Two worksheets from different data sources (databases) where one data source provides a date range and the other data source has a specific date that you want to include if it's within the date range. Seems like dynamic parameters would allow this. Hope we see those soon.