Looking for general questions on GTS

1) I'd like to use licenses to control shipments of products from state to state in the US. Is this possible? Region is not listed as a control object when defining the license type is it possible to add the field?

2) we are looking at connecting a second ERP system to GTS does the plugin used in ECC need to match the version of the ECC instance?

I saw a mention of having to harmonize master data? Is that only required if I put the two systems in the same logical group? If I create a seperate group for each will that require any harmonization?