creating a template for a generic url

Hi there

I have a custom content type

categories which makes up my secondary navigation

If a user selects a secondary nav option, the url is

/categories/{ option-name }

for which i have a single-category.php template

However, single-category.php lists another content type ie Holidays. Which are related to the category.

My Question is can i create a template ( or how do i ) that will catch all the holiday selected on any given category

ie i will have possible urls such as below::

/categories/{ option-name }/{ holiday }
/categories/mountain/everest
/categories/extreme/kiteboarding
/categories/jungle/newforest

etc etc

So the first two parts of url are fine in single-category.php but i can’t figure out how to define a template for last part given that i do not want to specifically define a template for everest, kiteboarding or new forest as they could well change or be any number of

Any help would be appreciated.

Thanks in Advance

Steve