IP settings
You can define the max number of IPs to allow per VM. it will limit the user to assign the IPs while creating or editing a VM. There are individual settings for IPv4, IPv6, IPv6 subnet and internal IP
Sever Group Preferences
You can select server selection preference from master setting, By default fist come first server algorithm will be applied. If Server Group has the preference then it will be the first priority over Master setting preference
You can select preference while adding and editing server groups wizard :