Sails.js/Waterline get Through association count, when filters are involved

Question

What I'm trying to do here is basically a mix of what was suggested for this question

User.count().where({follower: followerId})

and this question:

sails.models['user_phones__phone_users'].count({user_phones: userId}).exec(...)

So in other words I have a situation where I have three models: A, B and C. B acts as a Through association between A and C.

If I have a route that is basically A/:id/C?D=1&E=2

How can I get the results of C that are associated with A (through B) and match the filter of the query string (on D and E)?

At the moment it looks like count() works only with one model, but is there a workaround for this situation?

I know one idea would be to use a find (on A) with a populate (on C) and then count the populated associations, but in my case I have too many records and this solution kills the performance.

EDIT:

Filter criteria D and E apply to C. So they should be traslated to C.D=1 AND C.E=2 in SQL.

Also A and C are associated trough code:

// Model A
{
     attributes: {
        cs: {
            collection: 'C',
            via: 'as',
            through: 'b'
        },
     }
}

// Model B
{
     attributes: {
        a: {
            model: 'A'
        }, 
        c: {
            model: 'C'
        }
    }
}


// Model C
{
     attributes: {
        as: {
            collection: 'A',
            via: 'cs',
            through: 'b'
        },
     }
}