AutoMapper card for different types based on enumeration?

I'm starting to implement AutoMapper , the first I managed to integrate it with Castle.Windsor, which I already use. Now I have an object Postthat I want to map to either with LinkPostModelor with ImagePostModel. Both inherit fromPostModel

1) This is what I have so far:

public class PostModelFromPostEntityConverter : ITypeConverter<Post, PostModel>
{
    private readonly IPostService postService;

    public PostModelFromPostEntityConverter(IPostService postService)
    {
        if (postService == null)
        {
            throw new ArgumentNullException("postService");
        }
        this.postService = postService;
    }

    public PostModel Convert(ResolutionContext context)
    {
        Post post = (Post)context.SourceValue;
        Link link = post.Link;
        if (link.Type == LinkType.Html)
        {
            return new LinkPostModel
            {
                Description = link.Description,
                PictureUrl = link.Picture,
                PostId = post.Id,
                PostSlug = postService.GetTitleSlug(post),
                Timestamp = post.Created,
                Title = link.Title,
                UserMessage = post.UserMessage,
                UserDisplayName = post.User.DisplayName
            };
        }
        else if (link.Type == LinkType.Image)
        {
            return new ImagePostModel
            {
                PictureUrl = link.Picture,
                PostId = post.Id,
                PostSlug = postService.GetTitleSlug(post),
                Timestamp = post.Created,
                UserMessage = post.UserMessage,
                UserDisplayName = post.User.DisplayName
            };
        }
        return null;
    }
}

Obviously, the point in the AutoMapper implementation removes code repetitions like this, since I have to match common stuff before adding my custom rules (such as if-clause)

Ideally, I would like it to be something like:

public class PostModelFromPostEntityConverter : ITypeConverter<Post, PostModel>
{
    [...]

    public PostModel Convert(ResolutionContext context)
    {
        Post post = (Post)context.SourceValue;
        Link link = post.Link;
        if (link.Type == LinkType.Html)
        {
            return Mapper.Map<Post, LinkPostModel>(post);
            // and a few ForMember calls?
        }
        else if (link.Type == LinkType.Image)
        {
            return Mapper.Map<Post, ImagePostModel>(post);
            // and a few ForMember calls?
        }
        return null;
    }
}

2) . "" , IEnumerable<Post> :

public class PostListModel : IHasOpenGraphMetadata
{
    public OpenGraphModel OpenGraph { get; set; } // og:model just describes the latest post
    public IList<PostModel> Posts { get; set; }
}

, TypeConverter (?), , og:model

, , , :

public class PostListModelFromPostEntityEnumerableConverter : ITypeConverter<IEnumerable<Post>, PostListModel>
{
    public PostListModel Convert(ResolutionContext context)
    {
        IEnumerable<Post> posts = (IEnumerable<Post>)context.SourceValue;
        PostListModel result = new PostListModel
        {
            Posts = posts.Select(Mapper.Map<Post, PostModel>).ToList()
        };
        Post first = posts.FirstOrDefault();
        result.OpenGraph = Mapper.Map<Post, OpenGraphModel>(first);
        return result;
    }
}

3) , , ?

IEnumerable<Post> posts = (IEnumerable<Post>)context.SourceValue;

IEnumerable<Post> posts = context.SourceValue;