restore group "Limited Access System Group" on librairies

hello and sorry for my English,

 

i have lot of SharePoint website with librairies.

 

On this librairies, i have delete the inhenrit permissions to have unique permissions. After this i added users and group like i want.

 

but i have also delete the permissions to default group "Limited Access System Group", who was important.

how to restore this group to my librairies ? if i try to add permissions, the systelm don't find this group.

 

thanks a lot