Shima x Dan: My Life with Boys on an Island - oneshot by Yutori Houjou and Kako Mochizuki
Minato transfers to an island with population of 157 with 5 boys along her age. And she's the ONLY girl in the island along their age. I'm inspired to create another tag for this cliche: the "marriage game"! Think Arcana Famiglia and Hanasakeru Seishounen.