I am using Group module to implement "Group" functionality on my drupal site similar to what Organic Groups module implements. I have a user role community-leader whose users have been granted the permission (under People > Permissions) - Technology : Create New Group so that they can create new groups of type Technology, but normal authenticated users have not been granted this permission so they cannot create groups.
Group module provides separate permissions on its configuration/overview page under Group Roles. These group roles are for users involved in a particular group. In my case, users who create the group (essentially of Community-leader role or a user-role with higher permissions) are assigned Group-leader role and then there is a Group-member role supposed to be assigned to users who will join the group created thereafter.
For these roles (both Group-leader and Group-member), permissions like Join Group, Request Group Membership, etc. are disabled (no checkbox available instead a 'x' sign is present). I believe this is because since a Group-leader created a group, he automatically joined the group and there is no meaning of these permissions for him.
Note: The above roles (both Group-leader and Group-member) are global group roles, not group-type specific roles.
An authenticated user on my site is unable to access a particular group's page and thus has no way available to join the group. There is no granular(specific) permission available for this purpose. Moreover, even Group-leader or Group-member role users cannot access groups other then their own group. How to allow that? Could someone please guide me on Group Access Control for a better understanding?