Hi Scott,
Sure that's possible. I'm still not sure exactly what you are wanting to do though, can you explain more? You currently have a list stored in ListMail, and also on another server? So, when the alert comes from the other server that server is 'down', you want to then start sending the email from ListMail? Because that's the only way I see that working, you would have to maintain the list in both ListMailPRO, perhaps both are ListMailPRO installations, but either way, you would have to maintain the list on 2 servers, to make sure that is happening properly...
Even then, there are better ways to handle that. I maintain my lists in several email software applications (and providers) so if a server goes down, I just send from the other email provider, or other software application, instead of trying to maintain a duplicate list in LMP across 2 servers.
One problem with handling it all with LMP, is that LMP is not as accurate in removing bounces correctly, and it's better to maintain the correct list in another software application, such as Sendy (or SparkPost), etc... then duplicate the list(s) back to LMP on another server.