If you go over to the Content Exchange, there is an Alert Suppresion entry in there. I have not tried it on 9.5, but may be what you are looking for.
I'm a little confused. If you're not managing devices at your remote site through Orion, then you shouldn't be able to alert off of them.
One suggestion for monitoring connectivity with your remote site is the IP SLA Monitor free tool. You can create an IP SLA test using one of your managed nodes as the source, and target a device at the remote site.
Hope this helps,