The eDMX2 ports operate independently which means 1 can be DMX output whilst the other is a DMX input.
Send Art-Net to Port A universe -> DMX Output on Port A
Receive DMX on Port B -> Art-Net Output to universe configured for Port B
Some Ethernet DMX hardware will only operate as all ports Send or all ports Receive however eDMX is fully independent.
You probably don't need merging in this situation unless you wanted the Avolites console to control the blinders as well as LightJams. This gets a bit more complicated but if it's required drop me a note via our CRM page
https://shop.dmxking.com/crm.asp?action=contactus