@chessanalyst*You can register and offer those rooms here:
hospitalityforukraine.com*You can try contacting a local charity center, for example, Red Cross, and perhaps they can help you get in contact with local Lviv refugee organisers.
With all those refugees, I am sure both short and long term accommodations are a welcomed donation.
Currently Lviv is a huge refugee and transportation site for Ukrainians, who are either trying to get into the EU or want to stay in Ukraine, but away from the front lines.
@chessanalyst I applaud you for your initiative.