1. A method comprising: instantiating a plurality of service function instances for each of one or more hosts, wherein each service function instance corresponds to a particular service function type; grouping each of the plurality of service function instances into one or more service function groups, wherein at least one service function instance is a member of at least two service function groups established across one or more hosts; establishing a service function path for each of a plurality of service function chain types associated with the one or more service function groups, wherein each service function chain type comprises an ordered combination of one or more of the service function instances within each service function group and wherein at least one service function chain type associated with at least one service function group can comprise a number of service function instances that is less than a total number of service function instances associated with the at least one service function group; and maintaining loading information for each of the plurality of service function groups based, at least in part, on a number of subscriber Internet protocol (IP) flows assigned to each service function group.