Pooler (pgbouncer) + MasterDB + Slaves
Yes you can define in pgbouncer your 2 servers (or more) masetr and slave and connect to each of them.
There is different kind of topology you can install pgbouncer on each www, as is the connection will be the fastest (www process can use unix socket to connect), on install a pgbouncer on each server (master and slave) or install it on a new host to be single.
PErsonnaly I recommend another topology, install pgbouncer everywhere, on each www (to increase the connection), and on each db server, it will help you when you'll want to do migrations for example. PgBouncer support PAUSE/RESUME on connection, as is you can reconfigure your conenction on move traffic to master to a new host when you'll upgrade verison for example.