I've got Lucia, Desi's (and Mateo and Rafa's) sister, aunt to Rosa. While she helped bring up Rosa after her mother took off, she now owns a pretentious fashion boutique in Sol Nocte that caters to all the hoity-toity socialites and may or may not be a front for the family business. Her interests are many and varied, and I could easily see her supporting Zita's boutique - financially or otherwise. And possibly nursing just the slightest crush.
Would definitely love for these two to be in cahoots.