To setup Safari to automatically open mailto links within Gmail, please perform the following steps. This will install an extensions into Safari that's necessasry to accomplis this.
- Within Safari, go to this download page and downlaod the necessary extension
- Click Here
- Copy and paste this link:
Anytime you see an emailing address within Safari, when you click on it, it should bring you into whatever Gmail account you're signed into to send an email to that recipient.