Question:
Regarding a caterer, who is at one party and needs to deal with a situation at another party can the goyish waiter call up a goy at the other party put it on speaker and you give instructions over the speaker on the phone?
Answer:
Chas Vshaklom! You can not talk on a speaker phone on Shabbos, and even if you will tell the goy to talk instead of you, it is a terrible zilzul for Shabbos, to have Jew be busy on the phones, giving instructions to different goyim. This is precisely why chazal made the various restrictions on Shabbos, so that we should not get so involved, in business on the holy Shabbos, and come to make Shabbos into a weekday- like day.
If you are running more than one affair on Shabbos by all means hire a manager for the other affair. As a side point, it would be in your best interest to have a mashgiach that knows the halachos at your affairs to answer all of your questions.
