Private function in function template [on hold]

Suppose that I have a function template with a function foo. Now, for better readability I want to encapsulate different code parts of foo in other functions, within this template, but I don't want to these parts to be visible outside the template. But function templates don't seem to offer the usage of the "private" keyword. Is there a way to still hide code parts within a function template, or is it necessary to turn the function template in a class template?