Much of the interface and aggregation functionality exhibited by market segments is also available in the form of a generic Collection element. A number of elements of any type can be grouped together as a collection and then – if those elements are all of the same type – the corresponding input data can be compared directly from the icon for the collection. Aggregate results for the collection can be selected alongside results for individual elements of the same type – see 5.7 Viewing results for collections.
Unlike market segments, which are disjointed collections of services (i.e., a service can be associated with at most one market segment), collections can overlap with each other, allowing you to define arbitrary aggregation groups, and they can even be nested within other collections if you want to define a hierarchy of aggregation.