Vivint and ST Indoor Siren Integration

I have both ST and Vivint and use them separately and don’t have them linked together. Vivint is lacking in the ability to link two panels or key pads to the same account. I want to have an audible and visual in my bedroom when the alarm is triggered. I bought an after market indoor alarm Everspring SE812-US Z-Wave Indoor Siren. I was able to pair it and even set it up in Vivint, but Vivint’s capabilities are lacking. I can only trigger the Everspring alarm if the Vivint alarm is triggered by a door or window sensor being triggered, not by motion. If the motion is triggered it sets off the Vivint panel alarm, but not the Everspring alarm.

Can I connect the ST hub to Vivint or other way around, connect the Everspring to ST and set up an if and then statement that says if the Vivint alarm is triggered in any way that the Everspring is also triggered?

Thanks in advance!