Advice requested on best way to implement log4* to support non-hierarchal categories

My company is looking to standardize our logging across all of our C++
(and eventually Java) projects and we would certainly rather use a
well-known architecture such as log4j/log4cxx rather than growing our
own.

My biggest challenge is that one of the key desires our developers
have is to be able to mix and match the selectiveness of the logging. 
The easiest way to explain would probably be by example.

We would like to be able to easily mix and match any of the following
categories of log messages:
* performance/timing related
* search result related
* search result quality related
* any messages in the hierarchy com.foo
* no messages from the class/hierarchy com.foo.bar

We were hoping to be able to define the characteristics of log
messages within the class com.foo.bar so that we could have overall
performance log messages, search result performance messages, search
result quality messages, overall search result messages, etc. and then
via configuration we could say, "hrm, lets take a look at the search
result quality across all of com.foo.

Is anyone else doing anything like this out there?  I have done quite
a bit of reading on the log4j and log4cxx documentation, but I have
not found a good resource for explaining the Filter class hierarchy. 
Any pointers or advice is welcome.

Thanks,

Daniel E.