selctive route download

Hi, Can someone help me in selective route download using bird?. I did not see any specific configs. Secondly I don't want the routes learnt by bgp peers to be installed in the kernel but only routes that are stored in a file through some application to be downloaded to the kernel how do i do it?. The file can have both prefixes and next-hops or just prefixes? Any help is much appreciated. Thanks,