User management taking effect before relogin?

[SagaciousKJB]

Okay, I'm not sure how to ask this without being very complicated, so I'll just explain what I'm trying to do...

I have a program called xcet, it is owned by user root and group xcet, and the permissions are set so that only the user and group can execute it. When I attempt to append the group "xcet" to the secondary groups of a user in a root shell, and then attempt to run the program in a shell for that user, it doesn't recognize the group addition and gives me a permission denied error. "id -nG" confirms the group addition didn't take effect by not showing the group in the secondary list, but if I do "id -nG user" it will display the group at the end of the secondary list. It won't actually have any effect, however, until I log out and back in with the user.

Now that we've understood that, my question is whether there's any way to effect this change without having to log out and back in again with the user? This may sound silly, but I would rather not have to log out of my session, I've got a lot of things open that won't auto-restore, a couple of movies ripping, but I really need this permission change promptly. For now I've just chown'd the file to be owned by the user instead of root for a quick fix, but in the future I'd like to know if there is a way to effect these changes without the user needing to log out and back in.

[i92guboj]

As far as I know, there's no way to do that.

But I never looked too deep into it, so I might be wrong.