question about using memcached for shared web hosting

[Krystian]

Hi!
I'm looking for cache software which I can use in Load Balancing web 
servers (especially php sessions).
I'd like to know if it is possible to use memcached in transparent way. 
So users don't need rewrite code, just server create sessions in 
memcached. Also I'd like to know if it is possible to create different 
caches per user (for security each user gets his own session path).

Regards,
Hans