Multiple Email address for private key

[Kunal Shah]

Hi All,

My email program takes sender's email address and use appropriate
private key to sign the message. same way it takes email address from
"To" and use public key to encrypt the message.

I want to know if it is possible to have multiple email addresses in
single public/private key so that I have to use only one private key
to sign outgoing messages and I have to distribute only one public key
to get encrypted message for my 4 different email accounts.

Thanks