You can see your contact list and the contacts you can communicate with from the “Contacts” menu in the App.
From the all tab you will be able to see and contact with those contacts you share, at least, one group with.
To see all the groups you belong to, tap the Groups tab. Selecting any group, you will be able to see all the contacts in that group and contact them directly.
The administrator of the group has the control of the group's configuration and is the one that manages the group's members.
On the Phone contacts group you will be able to see, after your contact list is synchronized, any contact on your phone book using Enigmedia App, will be included in this group. The same thing will happen with any invited guest you may have: all invited guests will be grouped under the Guests group.
You will only be able to block the contacts from Phone Contacts you do not share any group with.