Yes, I understand and apologise, as I did understand you want to do A), but turns out you want to do B) (then C), D)), and B) results not possible with Toolset (and C), D) as well not), as you outlined since the begin it is an obstacle that cannot be overcome.
Let me remind you that we informed you about that twice as early on other tickets where we repeatedly stated "You need to do x to add repeating items", but due to MASSIVE misunderstandings, for which I am ready to accept all responsibility (but know am not entirely), we turned back assuming it's possible what you need to be done with Toolset.
Conclude:
It is not possible with The Toolset to achieve this.
Dear Beda,
Here is nothing to apologize (I believe), as we just try to find the best option (solution). I 'divide' (as I wrote before) applications on 'communication oriented' and 'content oriented' (Toolset). In other words, Toolset Forms are primary created to 'follow' CPT and custom fields and not as the 'form creator' itself (and there is nothing wrong with that). So, I just believe how I will be simply 'stupid' if I will not try to get more from Toolset (if that is possible) than I in reality should to expect. So, we tried and there is no 'end of the world'.
It is complete another issue, why Toolset developed RFG if we can't solve this very frequent and common 'real life' situations (scenarios), as here is about to repeat set of data, what should to be all of what RFG should to be, right?
So, if you agree, we can close this topic and I should to apply some other solution (quit from features) or to solve how to get to work third party solution (https://toolset.com/forums/topic/what-is-wrong-in-function-parent_post-get_the_id-parent/#post-1115180 - you can take it from Nigel also, if you wish).
https://toolset.com/feature-request/extend-current-post-forms-to-allow-many-to-many-connections/
This is a request to add Related posts in a Toolset Form just as used to, from the backend.
https://toolset.com/feature-request/allow-to-add-several-repeatable-field-groups-in-the-same-form-to-a-certain-post/
This is more particularly a request to add RFG's in a Post Edit Form as you are used to, from the backend.
I do really hope they get implemented, please upvote them here:
https://toolset.com/feature-request
(Search by the title of the above requests to upvote)
I would use those features myself if they were there.
Thanks for your patience and understanding!
I will take your reply as agreement that we can close the topic. Thanks for effort and contribution in 'clearance' of the issue (unfortunately, not solved issue).