Hi,
First let to say, as Rokas has pointed out, that the
RailClone plug-in is much more suitable for tasks like that. I would highly suggest you to use it for these purposes. You can check a sample of common bond pattern on
this related post.
Anyway, as the pattern is simple and regular, it's possible to archive that also with
Forest Pack. Just having in mind, that's developed mainly to distribute a huge amount of geometry and there is no specific tool for "joining items on the corner" / "slicing" or so. These areas need be solved by another Forest object(s) as on attached images. Feel free to check attached scene with showing that workflow. Hope that helps.
Kind regards,