I guess I don't understand the question, or maybe you're making it harder than it needs to be. Build all three reports. When you select Region = West from your main report, you'll see sub report 1 for West. When you select Customer Name = John, you'll see sub report 2 for West and John. I don't see why you would need or want actual links when mere selections will produce the same result. If you don't even want to see the sub reports until the user selects a Region and then Customer Name, use a conditional show on the layout tab, getselectedcount("Region")=1 for sub report 1, and getselectedcount("Region")=1 and getselectedcount("Customer Name")=1 for sub report 2. You might consider getpossiblecount() instead so that if other selections have narrowed you down to one region and customer, you don't have to still explicitly selected them. But maybe I'm not understanding what you want.
