"The scarf is 24 stitches across so I knit about 20 rows, then knit 12 stitches and did an end stitch,and knitted back a row.. ..continuing on for about 15 rows like I was knitting a mini-scarf only 12 stiches wide."
i can't think of any other way to do this either. I'd be interested if anyone else can think of a way. But, you know, it's not so bad to cut the yarn and start a new end of yarn. It gives you a couple more ends to weave in but that's not so difficult to do.