<form>
    <input type="text" name="title" />
    <input type="text" name="sinopsis" />
    [...]
</form>

<form>
    <input type="text" name="name" />
    <input type="text" name="model" />
    <input type="text" name="year" />
    [...]
</form>

<form>
    <input type="text" name="title" />
    <input type="text" name="director" />
    [...]
</form>

function insert_custom_post()
{
    // Treating $_POST variables sent from above forms
    // Executing wp_insert_post(...) according to post type
    // Redirecting to Home
    [...]
}
add_action( 'template_redirect', 'insert_custom_post' );