Actually that in my opinion, this should be automatic, when you create a bread the header should store a simple variable with the start number and the submit function should read a post and adorn the tag and colorize any link that is older. lb and pb is really a bad practice imo. It should just be styled with a different color, font, and size. This way on submit a simple function could read the post, check if it is less than the start-# and adorn the data. Ex.
start-#: 19935436
function(x){
{x start-#: (adorn-pblink) : return;}
}