How do you show / hide fields based on a group

How do you show / hide fields based on a group

Hi 

Could you please help

I have some control fields that are used by admin staff to control a users permissions. Such as setting the type of user in the portal, business user, general user, etc.

I cannot let the portal user see this information or edit it. I do need the admin logged in users to be able to change it.

As field permissions only all "Everyone" or "Admin"  (I would have loved this to be a user group - but I cannot find it)

I am using a method of show and hide.

I can turn on access for each individual 

"if (zoho.loginuserid == "zoho_test2" )
{
show Company_code;

}"


My question is.. How do i do this as a group?

Something like 

if (zoho.loginuserid == member.of.group.portal-admin )
{
show Company_code;
}


Any advice as the group permissions seem to be elusive to me.

Tony