Hi all,
I badly need your help in the below formula

Example:
Structure : Account includes Sub-accounts and each sub-account includes dials

Formula : Account activation date = Oldest Sub-account activation date
where there is more than one account and hence different activation
date for each account and in turn the sub-accounts that belong to each account

Below the example

A B C D
Account # Sub-Account # Account Sub-account
activation activation
date date

2 2.11 ?? 21-01-2010
2 2.12 ?? 26-01-2010
2 2.13 ?? 03-02-2010
3 3.111 ?? 14-02-2010
3 3.112 ?? 29-04-2010

Account Activation date for account#2 shall be 21-01-2010 (Oldest
sub-account activation date)

Many thanks,
Khaled