everything a user logs on, a folder appears with his/her name
The profile section will give a user access to their own home directory without needing to locate their home directory from all of the home directories. If you don't want users to enter their home pages but just offer a share available to a group, then comment out the [profile] section. Leaving your service for the group.
! comment = Network Profiles Service
! path = %H
! read only = No
! create mask = 0600
! directory mask = 0700
! store dos attributes = Yes
If you are seeing directories for each user, then you may have a [home] share defined that you can comment out.
Could you post the section for group service you are exporting? Also post the [General] section.
What kind of group are you referring to? Is this a group you created in windows with a policy editor? Or did you create a directory that a Linux group has access to? Did you add Linux users to a Linux group and make the share accessible by members of the group?
What Windows clients if any do you use? For example, if you have Windows XP Home clients don't even think about using the "security = domain" model. Windows XP Home clients can not join a domain.
If you have a samba-doc package available, please install it. It supplies three books on Samba; Samba 3 by Example; Samba 3 HOWTO & Reference Guide and Samba 3 Developers Guide. The first two you may find very useful. Also, if samba swat comes with your Samba package, then you already have the 2nd edition of Using Samba (in html form). They will take you step by step through the process of creating the share including what permissions to use, setting the sticky bit for globally writable shares and if you use smbpasswd, creating Linux users for each windows user and running smbpasswd to create a Linux/Windows username/passwd mapping.