Next/previous Posts from different categories

Hi,

I have maybe a stupid question but i have 3 categories of posts.
Each category has several posts.

When i display a single post, on the bottom of the post i have Next and Previous links, and this is OK for me.

The only problem is that once the last of first post of a given category is reach, WP still display previous/next link to jump to another category of posts…. And this i don’t want.

once reader is in 1 category of posts and there is “no previous” or “no next” post, the previous/next link should disappear.

How can i do that ?
thx.