Last fall, Jina Kim and two of her friends splurged on a two-night stay at the Ananti at Busan Cove, a luxury resort in Busan, South Korea.

The resort, where rooms start at $369 a night, features infinity pools, spas, eight restaurants, a private coastal walk and beach area, and a 4,600-meter “Water House” — an indoor pool and sauna fed by natural hot-spring water.

“We just spent the whole day in the resort hotel, swimming, eating and drinking,” said Ms. Kim, a 32-year-old former teacher who is now a stay-at-home mother.

Ms. Kim and her friends weren’t worried about how they would pay for the trip because they had spent over a decade saving in a “gyemoim,” a Korean term for people who form financial planning groups to save money for future expenses.

Forming gyemoim groups can help friends or families split travel costs equally so everyone can participate, regardless of his or her personal budget.

“Honestly, if we didn’t make the gyemoim, then it would have been too difficult for us to arrange that kind of trip,” Ms. Kim said. “It would have cost too much, and we didn’t want other members to feel pressured by that.”