|When you connect one switch to another, this is called daisychaining. When you daisychain switches, you aggregate the bandwidth on them. Say you have 4 switches|
Router >> Switch1 >> Switch2 >> Switch3 >> Switch4
In this example, switch 4 carries only the bandwidth of all devices plugged into it. Switch 3 also carries the bandwidth of all devices plugged into it which includes switch 4 and all it's devices.
Switch 2 in turn carries the bandwidth of all devices plugged into it which also includes switch 3 (and all devices plugged into it) and switch 4 (and all devices plugged into it).
Eventually, if you daisychain enough switches together, all traffic on them grinds to a halt as you've saturated the available bandwidth with more traffic than it can carry.
What wanderer is telling you is, if you plug switches into the LAN ports on the router, and only daisychain switches down one level, you won't abuse your available bandwidth and slow your network down.
I highly recommend you move away from the mickey mouse setup you've been running and spend a few dollars on some decent 16 port switches and plug them all into your router's LAN ports and then clients into them.
If your business is growing, you need to allow for future expansion.
I'd also highly recommend you move to a windows Active Directory based domain to ease the administrative load.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.