If I understand your desire correctly, no Ignition tag type will do what you want. Only scripting will transfer data from a tag pointing at one device to a tag pointing somewhere else (to produce a write).
Ignition v7.9 and prior had a feature on Expression tags that would write the result of each execution to a desired OPC server/item path combination. That was deleted for v8, and upgrades replace that function with a "legacy" tag value change event script that performs that operation.
So you could try a bunch of tag change value events that call system.opc.writeValue() or .writeValues(), but those are synchronous operations that are inappropriate in tag value change events in any non-trivial quantity. Consider a gateway tag change event subscribing to all of the necessary tags. If write traffic is high, you will want to batch by target device, so the OPC drivers have an opportunity to optimize. The use of a ConcurrentLinkedQueue and a timer event (to pace the write batches) would be appropriate. See this topic: