There are TLSin and TLSout reports that show which domains sent messages and recieved messages with TLS. They give the list of domains, and how many messages for that domain were TLS. You will have to contact support to get these, as they are not included by default on the system.
Yes the question has been answered! Support did add the agent for TLSIn and TLSout.
However, we also found the the inbound and outbound HTML reports have the detail of sender and receivers of TLS emails.