Decrypting E-mail for Other Users to Read

One of our clients sends us encrypted messages using S/MIME certificates. I
am the only user at our company that is set up to read the encrypted messages.

I understand that I can remove the encryption by forwarding the message
without encryption to another e-mail recipient.

We would like to decrypt the messages and save them up to our document
management system so that other users in our office can read the messages,
preserving the original message features (who sent it, and when it was sent).

Can this be done without a third party product/application?

Thank you.