Simplifying this IF structure
<p>Can you help me simplify this IF structure? This is javascript like node but something proprietary so ignore the db.execute stuff :)</p>

<pre><code>if(!("Division" in Shipping))
    {
        var shipError = false;
        Shipping.Division = Billing.Division;
        if(!Shipping.Division)
        {
                if(Shipping.PostalCode)
            {
                Shipping.Division = Db.ExecuteScalar("SELECT Code from Location.Division D JOIN Location.PostalCode P ON DivisionId = D.ID AND PostalCode=?", Shipping.PostalCode);
                if(!Shipping.Division) shipError = true;
            }
            else
                shipError = true;
        }

        if(shipError){
                Errors.push({Code : "SHIPPINGDIVISION", Message : "Shipping State Required"});
                Shipping.Division = "";
        }
    }
</code></pre>
