Assigning different due dates to multiple sections

[allegromus]

I am a lab coordinator for a large chemistry lab course with 14 sections (and 9-10 instructors). These sections meet on five different days of the week and require different open, due and closing dates depending on their meeting day. In the past I was able to set these dates for one assignment (across all 14 sections manually) then use a Copy Dates function (I don't remember the exact wording, but it was at the bottom of quizzes that had dates already set) to copy all of these dates to other similar assignments, offsetting them as needed. With the new "Assign to" GUI I cannot see an easy way to do this. (A previous solution was to create a giant Excel spreadsheet of due dates then copy & paste those dates into Canvas, which also will not work in this new format.)  It will be a huge task to manually set the dates for all 14 sections for every assignment since this currently requires at least six clicks to choose the dates plus another 3-6 clicks to set the times multiplied by 5 sets of dates per assignment - a minimum of 45 clicks to set the due dates for just one assignment. I have attached a screenshot of a typical set of due dates. Help!