Yes, you can do that very easy. Click on Safari menu on top or your borwser. When the window opens click the first icone (tab) and at the bottom of that window select the option open links from Applications "in a new tab in the current window." That is all you have to do good luck!
Omar
Go to Safari -> Preferences -> General -> Open links from applications -> in a new tab in current window.
Or go to Sarari -> Preferences -> Tabs -> enable all 3.
I don't think you read what the OP is asking for at all....
What the OP is asking for is analogous to the feature in Firefox that "forces" links that open in a new window to open in new tabs in the current window. There is no analogous built-in option in Safari. But SAFT and SafariStand should both be able to add this feature. This has been discussed a thousand times on MR....
I read it, and that is how I have mine set. It opens all links in a new tab.