What setting need to set to show list from contact for group of user

in security group
I created security group > add 2 member(admin and 2nduser) in that created group> add role in security group > in ROLES creat roles > in role setting set permission for contact module, if i set ALL, that time user able to see list of record which is imported by admin, if i change that to GROUP no other user able to see list of record. as far i know if i select Group that time i have to add member in security group which i did.

do you have any idea why its happen?
i add user/member in security group then why they not able to see list of contact?

include here few screenshot:

user role setting:

sec group setting: