roadblock n. a program broadcast simultaneously on more than one television channel. (source: Double-Tongued Dictionary)
roadblock n.— «The great advantage Reagan enjoys is the three-network whammy, what Matthews calls a “roadblock.” When Reagan speaks on all three networks at once, he is making it very difficult for viewers to avoid him, but...
roadblock n.— «The Minnesota Music Man and his newest label affiliation, Columbia Records, has hooked up with five Viacom music properties that will conduct what’s known in broadcast parlance as a roadblock. MTV, MTV2, BET, VH1 and VH1...