Populating Dropdown fields in dialog.xml

I have various different dropdown fields in my dialog.xml that i fill by calling a servlet using the options tag and then using the options root to say which JSONArray I want. This works well, however the same servlet calls an outside source and makes all of the JSONArrays so by having the options and options root on all nine of my drop downs it ends up calling the servlet nine times so it takes forever to load. Is there a way to call this servlet once, maybe in the root, and then access it by passing which options root i want in each dropdown?

ex.

<productsValue

            jcr:primaryType="cq:Widget"

            emptyText="Please Select..."

            fieldLabel="Property Value"

            name="./productsValue"

            options="path/to/servlet.json"

            optionsRoot="products"

            type="combobox"

            xtype="selection">

    </productsValue>