Tente desta maneira:
<AuthnProviderAlias ldap zzzldap>
LDAPReferrals Off
AuthLDAPURL "ldaps://ldap.zzz.com:636/o=zzz.com?uid?sub?(objectClass=*)"
AuthLDAPBindDN uid=zzz,ou=Applications,o=zzz.com
AuthLDAPBindPassword zzz
</AuthnProviderAlias>
<AuthzProviderAlias ldap-group ldap-group-yyy cn=yyy,ou=Groups,o=zzz.com>
AuthLDAPURL "ldaps://ldap.zzz.com:636/o=zzz.com"
AuthLDAPBindDN uid=zzz,ou=Applications,o=zzz.com
AuthLDAPBindPassword zzz
Require ldap-group cn=yyy,ou=Groups,o=zzz.com
#Require ldap-attribute employeeNumber=12345
</AuthzProviderAlias>
<Location /svn>
DAV svn
SVNParentPath /DATA/svn
AuthType Basic
AuthName "Subversion repositories"
SSLRequireSSL
AuthBasicProvider zzzldap
<RequireAll>
Require valid-user
Require ldap-group-yyy
</RequireAll>
</Location>
Não tenho certeza sobre a parte "Exigir o atributo ldap employeeNumber = 12345", mas o grupo funciona para mim agora.