An authentication system is configured to weight multiple available network supplied and user supplied authentication factors to determine whether a user should be provided with access to an Emergency Communication Network (ECN). The multiple factors may include the location of the user, MIN, short PIN, token, biometric information, and other information. The level of access to be provided to the user may be tiered based on the authentication level achieved during the weighting process. Authentication information may be shared between groups of individuals, so that the authentication requirements for group members may be reduced as other members of the group supply authentication information to the ECN. Group authentication may be used to enable group services such as conferencing and push-to-talk to be set up automatically for the group.