Schedules impovement

[on4bam]

Maybe I'm not using schedules as intended or I may have overlooked something but it seems using schedules could be improved.

First of all, I haven't used schedules before and just set some up recently. What I do now is enter a callsign and date and select DX Alert. Whenever that call is spotted the DX Alerts window opens and the spot is shown... yeah, success. However, in my recently set up callsign alerts I don't want all the spots.
In practice:
I have set up alerts for several ON75*** stations I haven't worked yet. I would like to be alerted for ALL ON75 stations but only if they haven't been worked  on that band. So no alert if the call is already worked on the band/mode of the DXcluster spot.

Can this be added (or can this be done already using another method)?