Mailto links as cc instead of new mail

Question

Explanation:
I have an Email A which contains email-addresses (not in CC of mail A, but in the body of A)
I need to write an email B to all of those, or some of those mail addresses. But if I click them, a new mail is being opened for every single mail address.
For now, I need to copy&paste it from the new mail into the "cc mail", which is stupid. So I need a solution, that puts mail addresses in CC rather then a new mail.
Any Ideas?

Answer 1

re ;if I click them, a new mail is being opened for every single mail address.
Yes thats is correct because you invoked a 'mailto' link to open a new message to send to a specific email address which auto uses TO to send to the one selected email address.
If you added those emaill addresses to your address book then you could use the Contacts sidebar to select your contacts and then use the 'Addto Cc' button option. Those contacts would then be available to quickly use on another occasion.
right click on email address and select 'Add to address book'.
By default this will add them to the 'Personal Address book'.
If you use the addon MoreFunctionsForAddressBook, this will also allow you to choose which address book, otherwise you would need to manually move the contact via Address Book.
See images below.