SmartShunt, how access data from second VenusOS installation

my Installation consists of two separate VenusOS installations with ESS, each has one MultiplusII connected. Those Multiplus are connected to separate Grids (apartment and server room) but share a common battery (Lifepo 48V 840 Ah) .
Thats seems uncommon but it works since 2 years well , and the purpose is to share the battery capacity for both areas of the building.
Now the question: the SmartShunt of the battery is connected to one VenusOS (Raspberry Pi), and I would like to use the data of the smartshunt also to be used for the second Raspberry/Venus instance.
I alredy tried to create the modbus entry on the second VenusOS with the IP address and ID of the smartshunt, but it does not show up as a device anywhere on the second VenusOS, except the modbus device entry.

Can that be done at all?