Setting the default calendar per user

As Executive Secretary, I use the calendar constantly to set appointments on the Bishopric calendar. Unfortunately, that's not the default calendar selection. I have (and will continue, I'm afraid) to forget to change this setting, and have sent personal appointments to the Ward Activities calendar, which always shows up as the first calendar in the drop-down. I don't always catch it, and it's quite an embarrassment to everyone involved.

Is there any way to change this default selection, please??