Can DTO's have nested DTO's?

I have the following domain model:

public class Playlist
{
    public long Id { get; set; }
    public string Title { get; set; }
    public virtual ICollection<Song> Songs { get; set; }
}

public class Song
{
    public long Id { get; set; }
    public string Name { get; set; }
    public virtual Playlist Playlist { get; set; }
    public virtual ICollection<Catalog> Matches { get; set; }
}

public class Catalog
{
    public long Id { get; set; }
    public string Title { get; set; }
}

My service has the following code:

public PlaylistResult FindByPlaylistId(long id)
{
    Playlist playlist = playlistRepository.GetById(id);

    foreach (var song in playlist.Songs)
    {
        song.Matches = catalogRepository.GetMatches(song.Name).ToList();
    }

    return new PlaylistResult(new PlaylistDTO(playlist), playlist.Songs.Select(x => new SongDTO(x)));
}

My service gets a playlist and songs from the database and then for each song in the playlist it fires a query to get additional matches from the database (using SQL Server full text search) specific to that song.

The data is then converted into DTO's, added to a result object and passed back to the controller. The code looks like:

public class PlaylistResult
{
    public PlaylistResult(PlaylistDTO playlist, IEnumerable<SongDTO> songs)
    {
        Playlist = playlist;
        Songs = songs;
    }

    public PlaylistDTO Playlist { get; private set; }

    public IEnumerable<SongDTO> Songs { get; private set; }
}

The problem:

The PlaylistResult object has worked great so far but the recent introduction of matches has made things a bit more complicated. It looks like I have no other choice than to modify my SongDTO to take into account matches and look like this:

public class SongDTO
{
    public SongDTO(Song song, IEnumerable<CatalogDTO> matches)