How to make a aggregate function in bird ?

Hello, I am attempting to make some intelligent stuff on one lab bird. I am sorry if this has been already asked since I do not have very mutch experience about bird, and some of my google:// didn't find what I am looking for. My idea is to find which aggregate I have within a bunch of subnet I have. For example : get_aggregate( 192.0.2.1/32 ) will return 192.0.2.0/24 Is there any nice way to make such function ? Also in the same work I would like to find how old is the route received in BGP. Any good pointers or examples are really appreciated. Kind regards, Xavier