Queston to material master Data

hi,

I have following problem:

I have different materials on the plant A. These Materials should be devided into two groups. group a is changeable for all people with the authorization to run MM02, group b should be only changeable for some spzific user, but not from group a.

How can i solve this problem? I think about the user authorization group, but I think it will be a lot of work to assign each material to a spezific group. Are there other possibilities?

The 2nd question is based on the first, so how can I make a restriction on the material, that the user from plant B is not able to change the material from Plant A? I tried it viea the organization level, but it does not work.

THX for your time in advance,

kind Regards

Markus