Sharepoint / teams permission for a site (sub-category of Members?)

[Rickytruco]

So I know that the different levels are Owner, Members and Visitors. 
But, I have several folder that certain people from a diferent section of the same Department should access, but no the rest of the Department. Instead of revoking access 1 by 1, I would like to know if I can create a sub-category of Members, (let's say MembersA) add all pertinent people there and the rest to the MembersB segment. 

[#2]

@Rickytruco you can't create a sub-category with permissions but if you go to the advanced permission settings page and create a new permissions group you can then select the appropriate permission levels, add the relevant people to that group and have the rest in another group.

Rob
Los Gallardos
Microsoft Power Automate Community Super User.
Principal Consultant, SharePoint and Power Platform WSP Global (and classic 1967 Morris Traveller driver)

[#3]

Hey @Rob_Elliott ty for your reply! This almost solves my issue. I created this in the main team Channel, but the documents I need to be segmented are in a sub-channel/site of that main one. On these sub-channel I don't see the option of advanced permission settings that let's me create the group. Or by creating it in the main one that should go through the sub one? I did that however, but couldn't get it to work either.
Mmmm so what do i do haha. Really appreciated the screenshot btw :)