我有個朋友公司，佢地用 netvigator 的公司 plan ...

netvigator modem -> sonicwall -> intel switch -> PCs

依家個 sonicwall 係 DHCP，例如 192.168.99.x/24 ...

依家佢地想裝多個 wireless router 俾公司的訪客用，佢地想可以上到網，但不可以訪問佢地依家的電腦。

是冇可以叫個 wireless router 再做多個 DHCP，而 assign 另一組 IP，例如 192.168.100.x/24?

buy an AP is ok lar.....  the most easiest setup

先create 另一個VLAN
再加隻AP/Router在那組IP上
而DHCP Server 可以由那隻AP/Router 去做
但就只派比那組subnet

just for information, for those Sonicwall with built wireless, the wired and wireless network are already on different subnet.

What is your Sonicwall model?

yes she is my daughter, u can just buy a AP to give out wireless from your current network
or just buy a wireless router to make a second network for your client only, like using a virtual ip as the WAN ip