react-router: Change URL without triggering re-route

I’m trying to implement a gallery that behaves like Instagram’s, but I’m having trouble due to the fact that I can’t change the URL without triggering a full re-route.

What I’d like to be able to do is open a modal from an image gallery and change the URL such that copying/pasting the URL results in displaying just that image and not the gallery behind it.

In other words, I have a set of routes that looks like this:

<Routes location="history">
    <Route name="index" path="/" handler={App}>
        <Route name="featuredGallery" path="/items/featured/" handler={FeaturedGallery} />
        <Route name="itemDetail" path="/items/:id/" handler={ItemDetail} />
        <DefaultRoute handler={Homepage} />
    </Route>
</Routes>

And I’d like to be able to visit /items/featured/ and click an item to open a modal that changes the URL to, eg, /items/10/?modal=true without triggering the ItemDetail handler (I will render it inside the modal in FeaturedGallery when an item in the gallery is clicked).

However, if /items/10/?modal=true were to be pasted into a new browser window, it should trigger the ItemDetail handler rather than FeaturedGallery.

If there’s a way to do this already, I haven’t been able to figure it out. Any help is appreciated!