Not sure what you are getting at but you can certainly have complex conditional find queries as in
find bo where (bo.attrib1 = a AND bo.arrrib2 = b) OR (bo.attrib1 = c AND bo.attrib2 = d) AND bo.attrib3 CONTAINS 'xxxxx'
How complex do you need it.
In a process or BO rule, you can certainly have IF THEN ELSE statements What you CAN'T have (or at least I've never got one to work) is an ELSE IF - but you can usually find another way round most things