Actually, you mean the IBL (Internal Banlists). There isn't a built-in feature to auto fill them, but I've written a script to do as much. I'll link to it.
It has a bug with Unreal IRCd in that Unreal can only do one /mode flag at a time, and it uses +q for owner status instead of quiet list.
Sorry about the size, it's mostly the comments that make it long, but readable.
https://gist.github.com/a-raccoon/004dcff7c79bebd15d03387e7d2590bf
