CD/DVD Drive Access with Virtual Box

My virtual box cannot access the CD/DVD optical drive. I know from reading that I need to add the cdrom group to the user but in OMV I can only see the users I have added not the virtual box user(s). I am sure I am missing something obvious but still learning my way around after moving from FreeNAS and am not sure where to fine the "user" to add cdrom group to.

Thanks,
Aaron

Isn't 3.x still in beta? Currently using 2 with Netatalk / SSH / Virtual Box plugins.

Fair enough. Thanks for the help, worked perfectly.