The Tyrell’s react to their own proposal from the Starks.
“Now, I know your father and brother have their little plots to make you queen. They seem to have overlooked the fact that there can only be one queen, and the job is currently filled. Being a high lady though, a lady of one of the seven great houses, can be just as good as being queen. Sometimes better. I was almost married to a Targayen, you know. I think this is not a marriage proposal to take lightly.” Lady Olenna gave Margaery a pointed look to emphasize her assessment.
“Who is it?” Margaery asked slowly, taking a sip of tea to hide any stray facial expressions that might betray her interest, or lack of interest, in the proposal of the moment.
“It seems the Starks of Winterfell are looking for a match for their eldest son, a boy named Robb who is very close to your age.”
You can read the whole chapter on An Archive of Our Own.