Unfortunately, this is still not possible, there is an open function request to do this. The only way you can specify it somehow is to provide the property --virtualbox-hostonly-cidrwhile you run the command createfor the docker machine, for example:
--virtualbox-hostonly-cidr "192.168.99.1/24"
dcoker ip CIDR 192.168.99.1/24. , , CIDR, /32, IP-.