Do mafia members need an obvious link?

[Mgm]

You don't necessarily need to link the roles, but the roles themselves need a good reason to be in the mafia to begin with. I usually link the kill power the scum use to their role somehow.

[Mgm]

For example, I had a Fruit and Vegetable Mafia game on the Grey Labyrinth a while back. The one mafia was linked because its members were green (but so were other players) and the other was linked because they were both round.

Both turned mafia because they were mistreated. No one liked to eat Brocolli and Brussel Sprouts, so they formed the green mafia and decided to bin other fruit and veg at night.

The others a pea and a grape IIRC were also tired of mistreatment and decided to juice a fellow player every night (I almost had to write a scene about orange juice).

There was no real connection between the mafia members apart from the flavor I gave them, but the rest of the town could only find out by speculating about the kill methods.