Field Group export in multi row?

Hi,
I’m using this plugin since some months and I’m really happy with it.
I would like to use the recent “Field Group” feature to simplify some information handling. The use case is :
A single person has to subscribe to different event in different dates, but in the backend we need an entry for each event.

I would like to avoid several form submission for the interested person and just use the Field Group repeater. So the flow I would like to implement is:
1. the user opens a form page and insert his personal data just once.
2. the user adds as many event date as he need (with repeater)
3. the form submission is exported to googlesheet with different format: a new row for each item in field group, something like:

row1: username, userphone, eventdate-1, eventdetails-1
row2: username, userphone, eventdate-2, eventdetails-2
row3: username, userphone, eventdate-3, eventdetails-3

I think this is not possible at the moment, nevertheless I have experienced a very good support on your side and I hope you could provide me with some hints for a custom modification of the export logic.
Many thanks