Today has been released version 1.7.11 of DidiSoft OpenPGP Library for .NET.
This version offers support for ADK (additional decryption keys). With the help of ADK we can encrypt silently for a list of multiple recipients by specifying explicitly only one recipient. The information for the additional recipients is contained inside the encryption key and can be modified if we have also its corresponding private key.
A tutorial chapter describing the new features can be found here: Totorial for using ADK.