Restrict access to an application using oauth2_proxy and Gitlab as its provider

I have currently set up a web-based application, to which I have added an authentication method using oauth2_proxy (with gitlab as authentication provider). What I need to know is if there's way that I can restrict the access to this app using a Gitlab group or something like that? Because as of now - oauth is configured to allow access to any user on gitlab which has a @foor.bar email domain (-email-domain=foo.bar directive on oauth config). However I'm looking to control this method in a more restricted manner, so for instance I will create a group on Gitlab, to which I will add only relevant users & other groups to which access should be granted. Is there a way to do it?