You are now able to buy different types of indoor units and connect to one condenser. First pick the indoor units: For example if you need 9k Wall Mount, 12k Ceiling Cassette and 18k Ceiling Concealed Duct you would pick those first and then matching condenser from 1st column. Condenser will normally be the combined total of all your air handlers. So in this case your condenser capacity is 36000 btu for example as it will easily cover 9k + 12k + 18 = 39k capacity using DC Inverter technology.