This topic should be in Networking.
In commercial use, a hub or switch should feed 16 users. In good practice there should not have to ever be more that two switches from any users to thew main server. But each office can has its own layout.
If the system is really several years old, like maybe over 15 years and has grown, it may be time to review the entire topology. You may need the help of outside consultants.
Something that complex can not be resolved with a few changes if it is a large system. How many workstations are there? Over 100?
You said 3 to 5 switches. That sounds very huge.