The relationship between Nick Carraway and Jordan Baker has some similar characteristics to the relationship between Daisy Buchanan and Jay Gatsby, but is not really influential in the dealings between Daisy and Gatsby.
Both Jordan and Daisy were basically interested in themselves and how they could have the best possible life with the most fun and money for their personal enjoyment. Men such as Nick and Gatsby (and Tom) were convenient to have around at times but were certainly not essential (although convenient to use for protection when needed) and were not worthy of expending too much energy or time.
Sometimes she (Daisy) and Miss Baker talked at once,...as cool as their white dresses and their impersonal eyes in the absence of all desire...making only a polite pleasant effort to entertain or to be entertained. They knew that presently dinner would be over and a little later the evening, too, would be over and casually put away.