Subitem dates in calendar view

On my content planning board, I have groups for each marketing campaign, then items based on type of content (email, social, web, etc.) and then subitems with the specific piece of content.

The publish date for the items (types of content) shows up on the calendar view, but I would like the publish dates for the subitems (specific piece of content) to appear on the calendar.

Is there a way to do this?