We plan to support this with the new driver. We had to update our TIA Portal in order to test this. The current plan is for the item paths to look something like this:
ns=1;s=[1500ss]PLC.Blocks."unit1.Unit_Block".Tag1
ns=1;s=[1500ss]PLC.Blocks."unit2.Unit_Block".Tag1
This is subject to change until we actually release, but this looks promising to me.