The Mainhall is the hub of the game having access to and vision of every other position in the game and those positions all exit out into the Mainhall.
Mainhall Tier Umbrella
The Mainhall tier in the sidebar contains not only the Mainhall position but also the positions of the Manager Suit, Assistant Manager Suit, Security Suit/Dog Suit and Table Suit. These positions are denoted by icons in front of the player's name. By umbrellaing Suits under the Mainhall Tier it allows the use of Suits while still being open to meeting requests.