Advanced AND and OR on simple structure

Hi,

For quite a simple table-structure, ie. Person, Criteria, and PersonCriteria (the combi-table), I have set up a query at the moment that selects alle persons that possess all selected criteria.

#arguments.criteriaIDs# is a coldfusion list with one of more IDs

The query itself looks like this at the moment:
Select p.PersonID
From Person p,
( Select Distinct PersonID, CriteriaID
From PersonCriteria
Where CriteriaID in (#arguments.criteriaIDs#)
) k
Where p.PersonID= k.PersonID
Group BY p.PersonID
Having Count(*) = #Listlen(arguments.criteriaIDs)#

sofar no problem and everything works fine. Now I want to offer the possibility for the user to add some AND and OR variables in their search, ie. someone could say: I'm looking for a person that possesses:

Criteria 1 AND 3 AND 4 (which would be covered by the query above) AND (5 OR 6 OR 7) AND (8 OR 9) etc....

I'm not sure where to start with this additional level.
I hope someone else does..
thanks!
Bart

select *
from <table> a,
<table> b
where
(condition1 = 'whatever' OR 1<>:variable_to_indicate_you_need_this_con1 )
AND
(condition2 = 'whatever' OR 2<>:variable_to_indicate_you_need_this_con2 )
AND
(condition2 = 'whatever' OR 3<>:variable_to_indicate_you_need_this_con3 )

Pass 1 for :variable_to_indicate_you_need_this_con1 to "activate" condition1. 2 to :variable_to_indicate_you_need_this_con2 to "activate" condition2..so on...

Cheers,
Me