I have a workbook with job satisfaction data for several units in
a large organization. The data is in a hidden sheet. All
respondents enter a code designating which unit they belong to.

The workbook user can view results for different units by entering
the right code into a "Filter" cell. The codes are hierarchical -
"1" produces total results, "1a" produces results for the "1a"
division, "1a1" and "1a2" produce results for two units in the
"1a" division, etc.

I want to distribute the workbook to managers at all levels, while
restricting them from viewing results from units they don't have
authority over. That is, the manager of "1a1" should be able to
enter codes like "1a1", "1a1a" or "1a1b2", but not "1b", "1" or
anything not beginning with his own code.

I kind of think it should be possible for me to enter the
authorized code in a password protected cell, and have the
"Filter" cell test the code entered against the code in that cell
before allowing it - but I don't have any idea how this could be
accomplished.

By the way, the "Filter" cell already has a validation rule
refusing any code containing a "?", as this represents a unit with
less than 5 employees. This validation rule runs like this -
translated from Norwegian:

=IF(ISERROR(FIND("?";Filter;2)<1);FIND("1";Filter; 1)0;FIND
("?";Filter;2)<1)

Would this really be possible??