Connections allows to add LDAP user groups to activities. To see the effective member list of an Activity, the group members need to be viewed.
Solution with HCL Connections provided tools
HCL Connections does not provide such a functionality. The group members needs to be fetched manually either via the ISC (Integrated Solutions Console) or directly from the LDAP. Then, every group member needs to be checked whether they are HCL Connections users.
Solution with Connections Administration Toolkit (CAT)
Navigate to Content And Access – Activities. Use the filters to search for the Activity you are interested in.