Board Thread:Support Requests - Getting Technical/@comment-79.119.101.81-20151027203130/@comment-4731443-20151027211442

I can't help you with redirects, but here is the full expression for your tag verification. I'll use several lines for clarity, but you can merge it into one: Line by line explanation:
 * 1) If tag 1 exists
 * 2) If tag 2 also exists
 * 3) If tag 3 also exists, we have all three, apply cat3
 * 4) (Else) Tag 3 does not exist, but we have 1 and 2, apply cat2
 * 5) (Else) Tag 2 does not exist, we only have 1, apply cat1
 * 6) (Else) Tag 1 does not exist, do nothing