This paper studies planar pursuit-evasion games that feature a group of players moving in an environment that may contain obstacles, where some players are pursuers and others are evaders. The goal of the pursuers is to capture the evaders, which requires the distance between one of the pursuers and one of the evaders to become zero. The goal of the evaders is to avoid capture. Specifically, this paper studies games with uncertainty in the parameters of the game, including the positions and speeds of the players as well as the positions of the obstacles. This work focuses on dominance regions, where a point in the environment is said to be dominated by one of the players if that player is able to reach the point before their opponent, regardless of the opponent's actions. In the existing literature, the use of dominance regions has been limited to games with perfect information about all players as well as the environment, and the key achievement of this paper is to extend the concept of dominance regions to practical scenarios where perfect information is unavailable.