I think that there are some similarities to FBP. However, I don't wish to pass them through filters that change the data passing through. I simply want all my bundled objects to meet associated conditions. For example. If I had a bunch of objects that represent components of a car:- wheels, hood (American term), doors, windscreen (British term), seat belt. These objects don't together make a car. But the suppliers of these components all have to meet a given safety standards, depending on the market for the car. You have already made your cars. Given that all other export conditions have been met, to what markets can we sell the manufactured cars? ie. Each market has a set of conditions that relate to each component type (object). And all these conditions must be met, without exception. There are some standards for particular components that are common across different countries and therefore replication of objects representing these safety standards would be silly. In addition, some countries do not have conditions for all component object types. And therefore, for some analysis, all the object types are not allways required. I am not working for a car manufacturer. However, my OO problem is the same. Are there any clever monks out there that can do a better job at explaining the OO concepts behind what I have just written? Or suggesting a practical approach to how I tackle this. Java or Perl, that is the main question.