Your BeoSound 3000 and BeoSound 4 are MasterLink (ML) but your BeoSystem 4 is not. It is NetLink (NL). To connect ML to your BeoSystem 4 you need a Beolink Conveter NL/ML. These are fairly expensive but could be a good "investment" for full integration if that is the way you are thinkingof going. All my system is the older ML so I can't really help with NL.
So my suggestion above using "option 5" is an experiment as I don't have anything to try it with.
Do you have a Beo4 remote? You can use that to set the option easier than the Beo5.
Stoobie
Devon,
UK