Hi,
as far as I understand:
10 experimental groups (sets)
Each set contains 5 groups of questions
Each group contains several questions.
Each participant is assigned randomly to one set or to one group?
I assume "to one group", as you create two random numbers.
Though I am confused, why you created two numbers (1,10).
LimeSurvey does not allow groups inside of groups.
So your design might be something like that:
S01G01 (1st set, 1st group) r1==1 AND r2==1
S01G02 (1st set, 2nd group) r1==1 AND r2==2
S01G03 (1st set, 3rd group) r1==1 AND r2=

...
S02G01 (2nd set, 1st group) r1==2 AND r2==1
S02G02 (2nd set, 2nd group) r1==2 AND r2==2
...
S03G01 (3rd set, 1st group) r1=

AND r2==1
...
S10G01 (10th set, 1st group) r1==10 AND r2==1
S10G02 (10th set, 2nd group) r1==10 AND r2==2
...
S10G05 (10th set, 5th group) r1==10 AND r2==5
This is what I understand.
But, sorry, I do not see your desired structure.
In these cases you always should attach a lss export of your survey.
Only a prototype that contains the relevant questions and the structure.
Or at least a sketch of the structure.
Joffm