Never mind. It turns out that you don't need the shout, because you can force the response. For example,
int n = 0;
object oNPC = GetHenchman(oPC, ++n);
while (GetIsObjectValid(oNPC))
{
AssignCommand(oNPC, bkRespondToHenchmenShout(oPC, ASSOCIATE_COMMAND_STANDGROUND));
oNPC = GetHenchman(oPC, ++n);
}