Is there a way to attach two email signatures in FYI?

You can set up a Default Email Signature for your practice.

You can also set up additional Email Signatures that are used instead of the practice's default.

When a non-default email signature has been set up, it needs to be selected in the User Profile of the relevant user(s) so it is used instead of the default. Refer to Managing Users.

 Refer to Creating Email Templates and Signatures.