APM - Override size limit for groups on local user db

Hi,

 

My display show me for the first time the below F5 error message when i wanted to add some new data in groups attribute for an user

 

 

After some tried, i found it's because I reached the maximum number of charaters authorised to save on groups attribute, limited to 127 characters (signed char?).

 

Can someone tell me if there is a way to modify the maximum size of this attribute or if it is an applicative limit ?