After the success of Galaxy Alpha which is the first complete metal body handset of Samsung the company move towards the mid range handsets with the same metal line.
The company revealed Galaxy Alpha last year which was the high end handset and a bit costly too but immediate after company released A series which is designed in the line of Galaxy Alpha but the A series handsets are the mid range according to the price. The present members of the A Series are Galaxy A5, Galaxy A3 and Galaxy A7.
And now company will add some new members which might call "Galaxy A6, "Galaxy A8", and "Galaxy A9". These handsets indicates the intention that Samsung want to increase their Galaxy a line and pointing out that Galaxy A8 and A9 are the high end devices than Galaxy A7 and Galaxy A6 is the middle specs version.
Still we don’t know the hardware configuration of the handsets but hopefully we known more about the Samsung A series soon.
Source (Translated from Korean)