Hello @christos,
Welcome to the forum!
Yes, this is absolutely the correct way. Since all VMs are working in the same physical place, they should not try to trick a node selection system to mimic a different physical locations, which will alter the default Storj network behavior and would allow to store more than a one piece of the same segment in the same physical location or for the same ISP, this will reduce the resilience and the customer may lost data if your server or ISP would go offline.
So, if you can get a public dynamic or static IP from your ISP - it will be a best way. You may also remove all VMs and run the Windows services with help of a @Vadim’s Win GUI Storj Node Toolbox directly on the server or using docker. This will significantly simplify the setup.