Is it possible to create nested groups in Red Hat Enterprise Linux?

Issue

• Is it possible to nest one group inside of another group, in Red Hat Enterprise Linux ? This would help to create a structure which allow multiple groups to have read/write permissions to some directories but only allow read to other groups.
  Example: A directory which needs read/write access by members of both group A and group B, so create a group C and define groups A and group B as members of group C. Is this possible with Linux groups?

• Is it possible to add one group existing on LDAP server (LDAP server could be any LDAP server for example, Windows Server or Red Hat Directory Server(RHDS) etc etc) as member of other group existing on local Red Hat Enterprise Linux?
  Example: Suppose a group named ad_grp exists on LDAP server and group named wheel exists on local Red Hat Enterprise Linux. Is it possible to add ad_grp as member of local group wheel?