[support] Shares a term with... in a View

[Larry Garfield]

Happy new year, everyone!

For our first support request of the year, I offer this bit of Views 2 
weirdness.

I have an Organic Group node type, Board.

I have a node type Rank, which is not in an OG.

I have a node type Character, which is always in an OG of type Board.

I have a taxonomy vocabulary "Rank set", which applies to both Characters and 
Boards.  

I have a nodereference on Characters that points to Rank nodes.

I am trying to create a View to be used to restrict the available Rank nodes 
in the nodereference field.  This View should restrict to Rank nodes that 
*share* one or more terms in vocabulary "Rank set" with the OG that it belongs 
to/that is the current OG context.  That is, if there are 4 terms and a given 
Board has 2 of them, then only those Ranks in one of those two terms should be 
included in the View.

I'm unfortunately a bit stumped as to how to do that.  So far I've tried 
adding a relation to a group node and then a filter on the taxonomy term of 
that group node relation, but that does nothing (or else filters out everything 
if I make the relation required).

Any other suggestions?

-- 
Larry Garfield
larry at garfieldtech.com