The name is a pun: "dor 3" refers to both the third generation, i.e., grandparents, and the 3G technology of cell phones.
Tamar and Yaron married and they had a son named Uri, who was killed for some reason (so they think).
The real story on Renen's father, was revealed in the first episode: Sunny Zorkin, CEO of Israel's largest cellular communications company, "Zorcom", grabbed it after guarding state secrets.
In a failed attempt to change his memoirs, escaping one of the scientists in order to Tamar Zehavi the information was shelved her all that much years.
But they're not alone: Several guys and girls of the younger and fresher generation: Yuval, Luda, Iggy, Chofni and Renen find themselves involved and become Hasamba's third-generation counterparts.