Hi, first of all this feature can be reachable in .NET with help of P\Invoke and WinApi.
General worfkflow process can be divided on the 2 stages:
1) Retrieving all pc's connected via lan to a single network.
2) Sending to each pc appropriate message.
First part of workflow can be feasible by using WinApi methods from native Netapi32.dll by calling such methods as:
And structure from this library called _SERVER_INFO_100
Second stage will consists from following steps(calling methods from wtsapi32.dll):
1) Get the handle of remote server by calling
2) Get the handle of active console session id by calling
3) Send message to appropriate server and console session with help of