How to create groups?

[John <ldap@thekeyboard.com>]

Hey guys :-)
I've just set up Openldap 1.2.6 and put all user's info in our organization
(about 30) into it for our internal use. Right now we're using it only to lookup
e-mails of users by searching by their First/Last name. My server is RH 6 Linux
2.2.12 kernel. All client computers are Win puters and using Outlook/Outlook
Express to lookup names on the Ldap Server. We have 2 departments in our org:
Wholesale and retail . I want to make 2 groups on my Ldap server, so by single
click user can send e-mail to everyone in either department. I've used
ou=Retail for every user in Retail dept and ou=wholesale for wholesale dept.
And there is an option in Outlook/OE to lookup organization, but it says that
nothing is found (I also have defined organizationname,department but it
doesn't seach for that either).
Am i doing smth wrong? What should i do to make this happen? 
Also my second question is:  What exactly do index: do? I've searched man pages and HTML help
file, nothing that gave a lot of explanation :-( Do they just force LDAP to
keep the data cached? If I use OpenLDAP,can I put just "index: <attr>" and it
will cache everything? What if I'll just Will it be a huge performance issue for
about 30 entries on local network + 100 ( i don't even now how many is gonna be
there  :-))) in the vendors/suppliers (when i'll make them)? 

Thanx in advance :-)

--
Windows leads to anger, anger leads to hate, hate leads to LINUX.