1. A method comprising: instantiating a plurality of service functions for each of one or more hosts, wherein each service function corresponds to a particular service function type; grouping each of the plurality of service functions into one or more service function groups; 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 functions within each 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.