Peter would an option for your condo be to "outsource" the issue.
Get a public charging company to install the units. This would mean the installation, insurance, billing would all be sorted for you. Of course it means someone is taking a profit but at least you have someone to maintain and deal with issues so there are no fights?
I don't know about Italy, but in the UK PodPoint (and probably others too) offer this service. Billing is all done through smartphone apps so no worries about allocation. You can even do stuff like having different charging rates for different users so you can have cheaper for residents, more expensive for visitors etc.
