Repating group inside repeating group

Hi i have 2 data types
1-Trips have filed
name text
participants list of users

name text
surname text

And i want to make repeating groups when in 1 will be trips and in second one will be list of all users which will have check box if user is checked they go on trip and i dont know how to do that pls help

i tried make repeating group inside repeating group by second dont have access to first but maybe i do somethink wrong

I don’t know if I really understand your question but is that answer you question ?

Is that answer your question ? If not, be more explicit or give some screenshots please