How do I thank my parents caregivers as they leave there care for a new facility?

My parents have been living in an independent living with enchanced care They have lived here for 6 years. They will be moving soon to a new facility to better meet their needs. The care they have received to date has been outstanding! And many of the caregivers have been with them through this time. They have become like family to us. I have been very involved in my parents care and multiple times each day verbally thank and encourage them. But I would like to give/do something a little more prior to moving my parents. There are 20 rotating caregivers. I thought about a luncheon but some would be unable to attend because it would not be during their shift and many of them work other jobs. Any creative suggestions? Thank you!