multiple ids on restful action


I know this question has come up before, but I couldn't find a
satisfying answer.
Maybe I didn't look well enough, so any pointers to old messages
regarding this subject would be welcome too.

I need some way to pass multiple ids to a resource.
Something like /posts/13,14
If I do this I have to manually split the id on ","s in the action,
and use
post_path([post1, post2].map {|x|}.join(','))
in my views, which I think is not very nice.

If I use post_path([post1, post2]) rails uses to_param on the array
which leads to the string "13/14" which is url-encoded to "13%2F14"
but the browser just shows a / in the next screen.
This is nice, since now the controller can split on "/" and I don't
need to do any string-manipulation in my views.
Only, if a user wants to enter the url by himself (/posts/13/14) I
will get a routing error because now the / isn't url-encoded. I can't
expect users to type %2F instead, which just looks ugly.
Now I could override Array's to_param method, but I'm sure there is a
reason for the default behavior.

So what is the preferred way to solve this? any transparent way to
handle this?
I mean ActiveRecord handles Post.find(13,14) just fine,
Post.find([13,14]) also.
Is there a way to make ActionController's routing automatically give
params[:id] back as an array if it detects some pattern? (something
like from_param maybe?)

Thanks for any help.

you could use *ids in your routing which would allow for an array of ids
using a non encoded /


And how can I do this on RESTful routes?
map.resources :posts ....

Will it work too if I use nesting?