Access control based on groups

[pinpox]

How can groups be used to grant or deny access to specific services?

I have multiple clients configured in dex and would like to allow only some of the users to access a selection of them. I figured I should use groups for that and define a group-based permission model, but couldn't find any examples on how to actually use the group memeberships to control access.

It would be greatly appreciated, if someone can give an example on how to set this up. I already have the users in groups on something like openldap, but don't know how to actually use these.