Littlewood-Richardson coefficients $c^\lambda_{\mu\nu}$ have numerous combinatorial interpretations, including the hive model by Knutson and Tao, see here. For other root systems, there are also several combinatorial interpretations, notably the Berenstein and Zelevinsky interpretation in terms of integer points in polytopes, see here. In the root system A, these are closely related to hives (see KT paper and also here). Despite extensive googling I can't seem to find the answer to this:

Question: What are hives for root systems BCD?

What am I missing?