Depending on your needs, I would not recommend to inject tracking from Instance 1 to an instance 2 in the OOTB tracking table. By the way the id of the recipient will be different from both instance and you will have hard time to reconcile freshly imported recipients with tracking. Second importing tracking in nms tables is highly risky as you need to embed linked object (url, etc. ...) to guarantee the system to work as expected.
For tracking I would then recommend to create a custom table like "historicalTrackingData", link it to recipient with proper type of link then store this information in this table. Then you can use it for targeting purpose.