Tableau will not connect lines if you are separating the worksheet out by subject area. You could easily show one subject area at a time, or have lines that break at each subject area, but getting them to connect will be a challenge, based on how Tableau works.
Which sheet in the workbook should we focus on, and can you simplify the workbook (remove anything we should not focus on)?
Also, can you explain why one college should appear as a line, while the others are bars? It just doesn't make for a great/easy to understand visual. Perhaps an alternative viz approach is needed here? It seems to be a good example of something Excel should NOT let you draw, as it doesn't make a lot of sense to connect a line over discrete dimension values.
Any chances you're interested in an alternative view? It would be easy to show all schools as lines, and with a dual axis, highlight/bolden the selected school line to differentiate it from the others. But using a bar for some schools and a line for another just does not make a lot of sense to me at first glance. Am I missing something?
The reason for the line is to easily display "our school" compared to a small selection of other schools. Over the years we found this to be the best visual display to easily recognise the difference.
I've renamed Sheet 5 and hidden other sheets.
The sheet in focus is now labelled Chart Display.
Unfortunately, very limited option is available on version 8.2.
Create parameter from school name
Put formula in secondary data source.
I only have version 9.2 as oldest which I attached.