LET'S POSE IN A HALLWAY: Backstage at his Hammerstein Ballroom show last week, RCA's Justin Timberlake rejoices with label and management players over hitting the 6 million worldwide sales benchmark with The 20/20 Experience. "Spectacular!" declared RCA chief Peter Edge. "Incredible!" gushed prexy Tom Corson. "Pastrami!" yelled EVP/GM Joe Riccitelli, who added,  "Oh ... did I say that out loud?" Seen thinking a plaque is better than 1,000 words are (l-r) Edge, EVP/A&R Head Keith Naftaly, Riccitelli, JT, Sony Music EVP International John Fleckenstein, Corson, SVP National Sales Bob Anderson and manager Johnny Wright. (7/14p)