This will give you the ability to install multiple versions of php side by side. (via: https://coderwall.com/p/vn1iqg)

multi_php

# More info - https://github.com/josegonzalez/homebrew-php#installing-multiple-versions

# install multiple versions of php with homebrew  
brew tap josegonzalez/php  
brew install php53 --with-fpm  
brew install php54 --with-fpm  
brew install php55 --with-fpm  

# These are the aliases that will auto switch to the version you want to use.  
alias use_php53="brew unlink php54 && brew unlink php55 && brew unlink php53 && brew link php53"  
alias use_php54="brew unlink php53 && brew unlink php55 && brew unlink php54 && brew link php54"  
alias use_php55="brew unlink php53 && brew unlink php54 && brew unlink php55 && brew link php55"  

# Below is an extended version I use when I'm controlling FPM services via Supervisor.  
alias use_php53="brew unlink php54 && brew unlink php55 && brew unlink php53 && brew link php53 && supervisorctl restart php5-fpm"  
alias use_php54="brew unlink php53 && brew unlink php55 && brew unlink php54 && brew link php54 && supervisorctl restart php5-fpm"  
alias use_php55="brew unlink php53 && brew unlink php54 && brew unlink php55 && brew link php55 && supervisorctl restart php5-fpm"  


# also avabile is phpbrew an alternate to the above options with more complex and advanced setup   
# https://github.com/c9s/phpbrew


==> Caveats
To enable PHP in Apache add the following to httpd.conf and restart Apache:
    LoadModule php5_module    /usr/local/opt/php54/libexec/apache2/libphp5.so

The php.ini file can be found in:
    /usr/local/etc/php/5.4/php.ini

✩✩✩✩ PEAR ✩✩✩✩

If PEAR complains about permissions, 'fix' the default PEAR permissions and config:
    chmod -R ug+w /usr/local/Cellar/php54/5.4.19/lib/php
    pear config-set php_ini /usr/local/etc/php/5.4/php.ini

✩✩✩✩ Extensions ✩✩✩✩

If you are having issues with custom extension compiling, ensure that this php is
in your PATH:
    PATH="$(brew --prefix josegonzalez/php/php54)/bin:$PATH"