Only show locations based on categories

Question

I am having trouble with categories, hopefully someone can help!

My site has 3 main locations (Eastern, Central, Western) and in each main location there are individual store locations. I am planning to separate each main location by categories. The locator also needs to have the "Search" functionality at all times.

Once you click on a main location you are taken to a page with a list of stores in that location.

Is there a way to hard code in the category (eg. category="7") anywhere that can limit the category on that template.

Below I've kind of made a hack, which is triggering the initial search for the main location, which is hiding the values of the search. This is working for me, but I feel like i should hard code in category="7" or something. What i've done feels wrong.

{exp:gmap:search
    channel="locations"
    latitude_field="location_lat"
    longitude_field="location_lng"
    geocode_field="location"
    distance_field="distance_max"
    cache_post="false"
    return="/map/western"}
    <ul>
        <li style="display: none;">
            <label for="location">Distance</label>
            <select name="distance_max">
                <option value="" &#123;if="" !distance_max="" ||="" distance_max="=" ""}selected="selected" &#123;="" if}="">Any</option>
            </select>
        </li>

        <li style="display: none;"> 
                <label><input type="checkbox" name="categories[]" value="6" checked="chcked" =""></label>
        </li>

        <li>
            <button type="submit">Western</button>
        </li>
    </ul>       
{/exp:gmap:search}

Let me know!

Thanks, funkefied