Queries - unable to use variant relationship

I'm trying to create a query that indicate wether or not a model (in a list of models) has a variant copy or not. My goal is to create a query that can help me in maintaining tracebility of model variants. 

My approach so far has been to use the formula QUERY_IS_CONNECTED(source item;target item;connection type;result string)

However, I can't find the variant relationship type when setting the parameters for the formula. Is the variant relationship not a valid connection type?

Is there anyone who can suggest a better approach? (I'd rather avoid scripting...)