Under Edit > Visibility > Who is allowed to see the guest list? you can choose whether you want all XING members to be able to see the guest list, or only those people invited, or just you. Remember though that if you choose the option Just me, the organiser you'll automatically deactivate the people2meet feature.
If you offer tickets or an online registration to your event, you'll be redirected to your XING EventManager. Under Edit Event > Sales Channels > Event on XING > Guest list settings, you can set the visibility of your guest list.