Your receiver isn't "8ohm". All receivers have a range of combined speaker impedance that they are stable to drive. If your receiver hooks the 2 pairs of speakers in parallel you would get about 3.4 ohms which is likely to be lower than it can drive.It can go into protection, blow a fuse, or blow up. That's why some receivers connect them in series, in which case. you would get 14 ohms which will produce less power but is safe. If the speakers are hooked in series then you can't use speaker B without speaker A. Check the receiver owners manual.
Now it becomes more complicated because you are adding super tweeters not another pair of full range speakers. Some of those are designed to be added to full range speakers and are safe. Others...