Let's look at the Akatsuki as a whole real quick. Look at the members. Madara, Itachi, Sasuke. Look at those three. They're related right? Well look at the Akatsuki uniforms. They're all the same right?
All of the Akatsuki are related. The uniforms gives it away.
Let's look at Itachi, Deidara, Pain, and Kanon. They all use eye liner, but not just any eye liner. THEY USE THE SAME EYE LINER. Madara wore a mask because of a horrible plastic surgery accident and he now wears the same make up.
All members of Akatsuki wear rings, which only adds support to them being related.
They obviously partake in family bonding. The ritual where they took the bijuu from Gaara.
Who takes what role in the family?
Here's the chart.
Messed up the chart. I'm fixing it.
Fixed the chart