Since I don't know the ages, I will count them all as women in the 2007 PalArab self-death count, now at 490.
UPDATE: Ma'an English adds more detail:
Gaza – Ma'an – A jeep disposed of three corpses in a deserted area of Deir al Balah, in the central Gaza Strip, and attempted to cover the bodies in soil, reported eyewitnesses and Palestinian security sources on Sunday.UPDATE 2: A car was blown up in Gaza, and another person died from the Fatah/Hamas infighting last month. 491.
The Hamas-affiliated Executive Force and medical staff discovered the bodies of three females. The cadavers were transported to Al Aqsa Martyrs Hospital in Deir al Balah.
According to Palestinian medical sources, there was evidence of knife wounds and suffocation on the corpses.
A Palestinian security source informed Ma'an that the corpses were identified as three sisters aged between 17 and 22. One of the women was married to a resident of Deir al Balah, the others lived in Gaza City.