From your help: (Lightstreamer .Net Adapter 1.7)
IMetadataProvider string[] GetItems(string user, string sessionID, string group);
"Called by Lightstreamer Kernel through the Remote Server to resolve an Item Group name (or Item List specification) supplied in a Request.
The names of the Items in the Group must be returned. For instance, the client could be allowed to specify the "NASDAQ100" Group name and,
upon that, the list of all items corresponding to the stocks included in that index could be returned."

The question:
The group "NASDAQ100" changes every few months, that is new stokes are entered or removed from "NASDAQ100".
How should I notify the clients about these changes in the items that constitute the group ?