Straight table group

[#1]

Hello Community,

I have a problem with my straight table, i want to create a fields to group my dimensions as on this following picture :

Thanks for the help

Teneman

[#2]

In fact i want to have like pivot table on big case Longueur at the left , and longeur 1 and longueur 2 for more details, i put the code dimension (that i hide in the presentation tab) because if i dont i'll not have a vertical table like this.

Hope that u understand, thnaks

[#3]

Other thing, the column at the left that i want to create is just for the presentation purpose (to group similar dimensions)

Thanks