keeping a post on top (without messing permalink)

Hi,

We want to keep a post at the top of a category. Example we are announcing an upcoming major event, but other smaller events/milestones are posted as well.

We thought that we had it solved by changing the publish date and didn’t realize that the month part of the permalink changed also which broke links.

We could change the permalink structure to get rid of time-stamping for posts but that changes existing posts (and maybe also existing media library uploads???) and will create more broken links. Though 301 redirects could handle this.

Suggestions Anyone?