I read this book in the 90s, but I think I may have been published in the 80s.
It was a modern era story. There are two sisters, one is responsible with an adult daughter getting married. I remember at least one woman wore a tartan sash across her chest, but I am not convinced it took place in Scotland, though it is possible.

The other adult sister is kind of a mess. Alcohol or drugs, perhaps? I remember her as the beautiful one who got all the guys, but deeply unhappy. It is mentioned that she wore Poison perfume, and it spills in her room.

I associate the color red/burgundy with this book, so it may have featured on the cover of the book.