No distracted by other pesky teasers elsewher *coughmiddleearthcough*. OK I have had a couple ideas but nothing that fits.
So I thought of Maedhros and Amras, - eldest and youngest of Feanor's seven sons (between us there stand five) but I don't recall they were particularly close. And naturally he was most alike to his twin.
Anar and Isil - stars and as blooms of the two trees closest when alive but the five I don't get.
Then Saruman and gandalf and the five is wrong again since five in total