Ikea factory workers organized by IAM, who will unionize the retail employees?

Ikea factory workers in Danville, Virginia, voted to unionize. Did they do it alone? No, they joined the International Association of Machinists and Aerospace Workers (Upside for Ikea, its customers can pretend their prefab furniture is tooled by rocket scientists). If Ikea retail employees follow suit, maybe there’s hope for organizing the poverty-wage employees of America’s largest private retailers: Walmart, Target, Home Depot, Lowe’s, so what current retail unions are recruiting their membership to flier offending locations, circulate among the workers and initiate organizing campaigns?