The RV320 has a feature called Protocol Binding that will allow you to link a single or a range of IP addresses on the LAN to use a specific WAN connection for an specific protocol.
Here is a document on how to configure such feature:
If what you are intending to do is to force, lets say a range of IP addresses on the LAN to only use WAN 1 as the outbound connection for all the traffic, then you want to configure the protocol binding as follows:
Service = Any
Source IP: Beginning of the range or single address
to: End of range or singe address
Destination IP: 0.0.0.0 (Anywhere on the internet)
to: 0.0.0.0 (Anywhere on the internet)
Interface: WAN 1
Status: Mark the checkmark to enable it.
Please remember that you can Bind the protocols via IP addresses and no specific LAN ports.
I hope this helps
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