Url_for, routes, and the current url

I need to generate 2 types of URL and have defined my routes as:

yes”, :controller=>“posts”, :action=>“country”, :yes=>true
no”, :controller=>“posts”, :action=>“country”, :yes=>false

map.yes “/yes”, :controller=>“posts”, :action=>“index”, :yes=>true
map.no “/no”, :controller=>“posts”, :action=>“index”, :yes=>false

The problem is that, when a request if for /yes or /no, url_for()
doesn’t generate URLs for the country.

url_for(:yes=>true) generates the correct url no matter where its
if the current request is for /no it generates /yes.
if its for /mexico/no, it generates /mexico/yes

though this is not the same when trying to generate URLs for country.
If the request is at /no
url_for(:country=>‘usa’,:yes=>true) generates /no and tacks on ‘usa’
and ‘yes’ as query string parameters instead of generating /usa/yes.

Why is this taking place?