There is one shammash at a time. When the rebbe started being half a year in eretz yisroel and half a year in america, a second shammash was set up for eretz yisroel. When the rebbe got sick the shammash would travel with the rebbe. I was shammash in between my older brother and the next one. My duties were to bring the rebbe to shul and back. Being that I was a shammash after he re-married, I did not have to take care of him in his house as his wife was capable in doing so herself.
😀 Zuberman! 😀