Yes and no. The mandrill plugin just tries to send the email through the mandrill service. We have no clue what the content of the mail is. You'll have to hack the code and try to extract what you need.

"Is it possible to sent an e-mail to a new registered user only and not to all the users with "Receive System Emails" field enabled?
It's not the cmandrill plugin sending the mails, but the joomla component you are using. So doing such modification should be made there.

Regards,
Daniel