Sorting groups as block depending on there "header/title"

[joujouba]

Hello,

I am looking to sort this file by "start date", from oldest to newest start date.
There is 3 groups, each of them is for 1 Student, I don't want the data inside the group files to be sorted, I want the whole groups to be sorted according to there "title" start date (there title is the writing with bold character and thick borders)

My problem raise is that I can not attach each title to its actual block/group.

The result I'm looking for is being able to sort (while groups are all collapsed/minimized) the groups according to there start dates that is shown in the always visible title, once sorted the whole groups will move along with there titles to the right order.

I really hope you can help me, I have been trying to do this for days now
I extremely appreciate it!

Thank you all in advance

[joujouba]

Help plese