Showing user trace in group calendars

HiI’m using LN 6.5 and I’ve just created a group calendar where I can see and even modify entries in other users’ calendars. But I also need that when another person, with reader access to the same group calendar, check over some user particular entry that I’ve modified, that person could notice that the change I did, was effectively done by me.

What could I do to achieve that effect?

Thanks in advance

Kymay