Need clarification on temperature control rules

Hope this post is in the right place. Can someone clarify the requirements for safe temperature control and what this means (or  how it applies) when it comes to making pho? It seems a bit challenging in a restaurant to control temperature for large quantities of hot broth. Say I make 60 gallons of pho broth at a time. Regulations normally give 2-4 hours before you have to cool to 40-42°F, but it would take a lot longer than 3-4 hours to cool this quantity. Help!

Thanks.