@Boydie
You are thinking along the right lines...
Here is my idea..
Seven Deadly Brothers
Luxuria (Lust)
Gula (Gluttony)
Avaritia (Greed)
Acedia (Sloth)
Ira (Wrath)
Invidia (Envy)
Superbia (Pride)
Luxuria takes Acedia's wife, Avaritia takes his possessions, Acedia has given up and doesn't care. Invidia is envious of Avaritia's rich life, while Superbia thinks he is the best, most successful brother. Gula is Avaritia's twin, he is the loner, he lives alone, eats lots and collects riches. Ira is the angry, bitter brother, frustrated at what his family has become. He is determined to punish them for their ways.
Each brother has his own story, his own personality, his own 'sin'. Each affects the other in some way. Well, something like that..