External Text Files into HTML page

Hi all.
I have a fair understanding of PHP, can modify basic scripts, but can’t write any myself.

I am working on a website (PHP based running off templates).
Now, the site has a series of different categories. On each category’s page there is a series of links in the footer.

I am wanting these links to be contextual for example, on a page about broadband, I want a set of specified links all to do with broadband displayed in this footer. in the mobile phone category page, there is a seperate et of specified links displayed.

Now, I have worked with Flash and external text files before - loading variables from external .txt files.

Is there a way to have the same sort of thing in HTML, below is an example of what I’m thinking:

URL to each category page will be www.mysite.com/broadband**?linkset=broadband**

Then somewhere in the PHP template I would reference an external text file, which would contain the following:

broadband = <a href="’#">Link One</a>,<a href="’#">Link Two</a> etc

I am probably going about this the completely wrong way, and I know there would be some scripting needed,but I hope the explanation is clear.