Merge Dependency Injection Parameters by key

I am new to Symfony. I need to create likely 2 or 3 separate bundles. Each bundle extends DependencyInjection providing an array typed parameter with key:navigations but with different values.

nav.xml on bundle page:

<parameters>
    <parameter key="navigations" type="collection">
        <parameter key="page" type="collection">
            <parameter key="label">Page</parameter>
            <parameter key="url">%admin%/page</parameter>
        </parameter>
    </parameter>
</parameters>

nav.xml on bundle blog:

<parameters>
    <parameter key="navigations" type="collection">
        <parameter key="blog" type="collection">
            <parameter key="label">Blog</parameter>
            <parameter key="url">page</parameter>
        </parameter>
    </parameter>
</parameters>

when I do:

$nav = $this->container->getParameter('navigations');
dump($nav);

I only get last defined parameters. How should I merge them ?