Ask samba File Sharing questions?

Ask samba File Sharing questions? -- Linux Enterprise Application-Linux server application information. For details, refer to the following section. Rhel5 configure samba
1. Add two users: user1 and user2, smbpass-a user1 and user2
Create directory share and Modify host chown-R user1.user1/usr/tmp/share
Change permission chmod-R 777/usr/tmp/share
Smb. conf is as follows:
Security = user
[Share]
Path =/usr/tmp/share
Valid users = user1 user2
Public = no
Writable = yes
Write list = user1 user2
User1 logs on to create a file or folder. user2 does not have the permission to add, delete, and modify file content ??
2. Similarly, create a group of users
Useradd group
Useradd-G group user1/user2
Smbpasswd-a user1/user2
Chown-R group. group/usr/tmp/share
Chmod-R 777/usr/tmp/share
Smb. conf is as follows:
Security = user
[Share]
Path =/usr/tmp/share
Valid users = @ group
Public = no
Writable = yes
Write list = @ group
In the same case, when the two members in the group have the same folder host as the group, they cannot modify each other's file name or content after creating files. Thank you for your advice!