Managing Alerts

Hi, I’ve OF on an iPhone, iPad and an iMac which is really great. Is there an easy way of syncing to stop alerts for actions on one device that I have already completed on another.

When working at my iMac I do not use my iPad, why would I? Yet, my iPad will alert me to do an action that I have already marked complete on my iPad.

I do not want to disable alerting on my iPad as when away from my iMac I rely on the alerting.

Any suggestions welcome.