Item Exclusion

What is the algorithm for allowing a unit to carry only one type of an item. For example, one weapon, one shield, one chest piece, etc.

Thanks ahead of time

The easiest way to answer this is to suggest you explore the resource and tutorial databases: I'm sure explanations and examples of inventory systems are available that should point in the right direction.

u need to define which item belongs to what part and then check this everytime a unit pickup something. or you can make custom inventory...