9.4 and centos/yum multiversion installs

I have a CentOS 6 server thats already running 9.0, ... 9.3 for development.

I added 9.4 to it by ...
     yum install
http://yum.postgresql.org/9.4/redhat/rhel-6-x86_64/pgdg-centos94-9.4-1.noarch.rpm
     yum install postgresql94{,-devel,-server,-contrib}

I created /etc/sysconfig/pgsql/postgresql-9.4 with...
     PGENGINE=/usr/pgsql-${PGMAJORVERSION}/bin
     PGPORT=5436
     PGDATA=/var/lib/pgsql/${PGMAJORVERSION}/data
     PGLOG=/var/lib/pgsql/${PGMAJORVERSION}/pgstartup.log

(same as all the others except a unique port)
and initdb via..
     service postgresql-9.4 initdb

all good so far.  but when I ...

     service postgresql-9.4 start

it fails, leaving the following in pgstartup.log...

     < 2015-09-29 09:38:15.270 PDT >LOG:  could not bind IPv6 socket:
Address already in use
     < 2015-09-29 09:38:15.270 PDT >HINT:  Is another postmaster already
running on port 5432? If not, wait a few seconds and retry.
     < 2015-09-29 09:38:15.270 PDT >LOG:  could not bind IPv4 socket:
Address already in use
     < 2015-09-29 09:38:15.270 PDT >HINT:  Is another postmaster already
running on port 5432? If not, wait a few seconds and retry.
     < 2015-09-29 09:38:15.270 PDT >WARNING:  could not create listen
socket for "localhost"
     < 2015-09-29 09:38:15.270 PDT >FATAL:  could not create any TCP/IP
sockets

does the 9.4 yum install no longer support using the sysconfig settings
fragments ?  I see what looks like the correct shell code for it in
/etc/rc.d/init.d/postgresql-9.4 ...

     # Override defaults from /etc/sysconfig/pgsql if file is present
     [ -f /etc/sysconfig/pgsql/${NAME} ] && . /etc/sysconfig/pgsql/${NAME}


....arrrrgh, comment in /etc/rc.d/init.d/postgresql-9.4 would suggest so...


     # Version 9.4.0 Devrim Gunduz <devrim@gunduz.org>
     # Remove PGPORT variable

so... how do you run multiple versions??

--
john r pierce, recycling bits in santa cruz