This year’s cohort of Israeli and Palestinian entrepreneurs taking part in 50:50 Startups is smaller than usual, because the war prevented many from travelling. 50:50 co-founder Amir Grinsteen (third from right) founded the program seven years ago, believing that building businesses together would also build lasting bridges, that could advance the cause of peace. Dena Yadin hide caption toggle caption Dena Yadin BOSTON – Salah Hussein was 11 years old when he was woken up in the middle of the night by Israeli soldiers in his family home in Nablus in the West Bank. It left him traumatized and terrified for years. It was “triggering” to see any Israeli in uniform, he says. “For me, all of them were a threat.” But decades later, Hussein, now a 33-year-old entrepreneur, has willingly and purposefully tied his fortune to his co-founder, who is an Israeli Jew. Hussein is one of about 35 entrepreneurs taking part in a start-up accelerator program called 50:50 Startups, where mixed teams of Palestinians, Israeli Arabs and Israeli Jews spend six months in …