We now have a computed group of party members, but now we want to be able to know who in that group has low health, so we can create an IComputedCollection
which is already constrained to the party (so we dont need to worry about working out that bit again), then we can check if their health is < 20% and if so put them in the list with their HP value, this way we can just bind our whimscial PartyMembersWithLowHealthComputedCollection
which would implement IComputedCollection<PartyMemberWithLowHealth>
(verbose I know) in the DI config then inject it into a system and boom you now have a system which can just look at this one object to find out whos got low health and be notified when anything changes.