Compartmentalization describes the strategy of only telling someone what they would know about or find out anyway. In this way, no one person knows a lot about the compartmentalizer. Generally, this is a shame-based strategy that supports a shaky self-esteem by seemingly giving others less to criticize. It also supports power behavior, because knowing something someone else does not certainly gives the feeling of power and can often give actual power over another.
Compartmentalization supports the con very strongly, because when people try to pin the primary aggressor down, they still usually end up distrusting and doubting each other anyway. Compartmentalizing, combined with insincerity, easily pits third parties against each other enough to distract from the main issue. Sometimes other people are led to believe they are in a privileged compartment, and so they may come to support the con to become closer to the conning person.