Record inactive ip

Greetings...
First time poster ancient fan here.
This is neither an issue nor a pull request... so pardon the out of topic mode.
This is more a feature request.

I would like to suggest, beside the dead, alive and all status filter... please provide one that list KNOWN ip. So for instance... If first time scan yield 20 ip.
Any scan done later, unless there is an addition, must also yield 20 ip... consisting alive and dead host.
That way AngryIP can be use as monitoring as well.

If the known ip is really no longer use, status can always be declare as "available" for instance.

That's about all I'd like to ask.
I wish I know java... and contribute in a more useful way.

Many thanks in advance

Paul
Jakarta, Indonesia.