I have a StockFinder 5.1 layout with a watchlist of stocks (List A) and a daughter watchlist of stocks in the Sub Industry of the active stock in the first (List B).  I have 2 charts that display price history plots of whatever stock is selected in either of the lists.  This is easy.

I want to restrict the main chart to only display price information for the stock selected from List A and the second chart to display only price information for a stock selected from List B.

I think my problem is I just can't figure out which block to select for each chart.

You could just add an Industry Group Price History indicator to the chart where you want to plot the sub industry. You would edit it to make sure the Industry setting is set to Morningstar Sub. You would then be able to delete the main Price History indicator from the chart.

Another option would be to edit the Block Diagram of the Price History indicator to but a Morningstar Sub Group Symbol icon between the Bar Chart Symbol and Price History Blocks in the Block Diagram.