As discussed is #31 adding new types of filtering tiles is hard.

All group members need to work correctly, if not it can f up the whole group. This is the reason I made the filtering member a abstract class and not an interface, but it is very hard to create working integration with other mods (like IronChests). I basically need to copy all functions of that mod into a class in Block Extenders, which is something I'd rather not want to do. I'd like to brainstorm with you about a good way to do this, there might be a way I do not know.

I might have a solution for this:
The tile should implement an interface with a method that returns a FilteringHandler class. This class will handle the grouping and inventory stuff. This will allow for a closed, hard-to-temper-with class, but is easy to implement for other TilesEntities (it's just an interface).

More suggestions?

This is more or less resolved.