Hi,
You do what you want, Wampserver is licensed under the GNU GPL.
To be able to have different PHP versions assigned to VirtualHost, you would have to run PHP as FCGI, which is not the current case for Wampserver where PHP is run as an Apache module.
On the other hand, you can set different PHP configuration parameters for each VirtualHost, but for the same version of PHP.
---------------------------------------------------------------
Documentation Apache -
Documentation PHP -
Documentation MySQL -
Wampserver install files & addons