Aw, I don't play Orcs, I only have Skavens and a small beginning of an Empire army, but I have put WH on hold for more than 2 years now, I'm a bit out of synch...
On the other hand I have Orks and Chaos Marines, but oh well...
Are there WAAGH! rolls when charging in Battle ? maybe you could add drinks when Grotz fail their bickering rolls... Or get the opponent to drink heavily if a designated hero makes x successful wounds in a single roll.