Let say I have one post with tittle "Dummy one" and that post is filed under "Category one" and i have other post eg : "dummy two, dummy tree, etc" and category two, category three etc.

and now I create other post with title "helper for category one"
how to display permalink to "helper for category one" in all post with  "category one"

I want to put it under `the_content();` in single.php.

let say my single.php is like this

    if( have_post()):
    while( blah blah ):
    the_content();
    endwhile;
    endif;


i want to like this.

    if():
    while():
    the_content();
    if(category == "category one"):
    display_helper_for_category_one
    else:
    display_nothink
    endif;
    endwhile;
    endif;

can I do that ?
if can How?

if any wrong grammar I'm sorry.
i cant speak/write English well.

thanks for adv.