Of course, I use the available SCL pakages from the SoftwareCollections project site, especially the httpd24, php54 and php55 collections.

RHSCL 1.0 repository configuration for RHEL-6 (php54):

rhn-channel --add --channel=rhel-x86_64-server-6-rhscl-1

php54 repository configuration on CentOS-6 as RHSCL-1.0 is not (yet ?) backported:

wget http://people.redhat.com/rcollet/php54/rhel-php54.repo -O /etc/yum.repos.d/php54.repo

httpd24 repository configuration: 

wget http://repos.fedorapeople.org/repos/jkaluza/httpd24/epel-httpd24.repo -O /etc/yum.repos.d/httpd24.repo

php55 repository configuration :

wget http://people.redhat.com/rcollet/php55/rhel-php55.repo -O /etc/yum.repos.d/php55.repo

Apache 2.4.6, PHP 5.3.3, 5.4.16 and 5.5.5 packages installation:

yum install httpd24 php54 php54-php-fpm php55 php55-fpm php-fpm

As the 3 php-fpm versions are configured to listen on the same port I have to change this:

sed -e 's/9000/9002/' -i /opt/rh/php54/root/etc/php-fpm.d/www.conf
semanage port -a -t http_port_t -p tcp 9002

sed -e 's/9000/9003/' -i /opt/rh/php55/root/etc/php-fpm.d/www.conf
semanage port -a -t http_port_t -p tcp 9003

Apache configuration for delegating the PHP scripts execution to a php-fpm back-end, according to the version, The new /opt/rh/root/etc/httpd/conf.d/fpm.conf file:

#   PHP script executed by FPM backend
ProxyPassMatch ^/php53/(.*\.php)$ fcgi://127.0.0.1:9000/srv/website
#   Other static stuff
Alias /php53 /srv/website

ProxyPassMatch ^/php54/(.*\.php)$ fcgi://127.0.0.1:9002/srv/website
Alias /php54 /srv/website

ProxyPassMatch ^/php55/(.*\.php)$ fcgi://127.0.0.1:9003/srv/website
Alias /php55 /srv/website

I choose to configure the 3 URL to serve the same folder as my goal is to test the same applilcation with various PHP versions.

I could also have configured various virtual hosts.

Prefered web application installation:

mkdir /srv/website
echo '<?php phpinfo()' >/srv/website/info.php

Required services start up:

service httpd24-httpd start
service php-fpm       start
service php54-php-fpm start
service php55-php-fpm start

Just enjoy: http://localhost/php53/info.php or http://localhost/php54/info.php or http://localhost/php55/info.php

Notice: this is a very simple configuration, for development/testing purpose. It will requiring more tunning to be used in production, but it's working.