What are the effects in parts requirement when the item relations are: Suppression or related or sub

Hi,

I want to ask what is the behavior of the application inside the parts requirement when the required item has a defined relationships in inventory like:

- Suppression

- Related

- Substitute

Does the system suggest different item instead on the original item based on these relations?, or these relations are not considered in spares management? Are all item relations supported or some of these relations only?

Thanks