If you use >AS7 it is possible.
What you mean by same datasource different driver version.
In AS6 you can have only one driver in the lib directory. With AS7 you might have different driver versions, but you need to configure different datasources for that.
One possibility is to include the driver in your deployment and set the classloader for AS6 accordingly in the applications.
But why do you need it, mostly a new driver can handle older versions of Oracle without any problem.
I need be careful, in other times I had problem.
For defined datasources (*-ds.xml) I see no chance to have several drivers with AS6 you need to migrate to AS7 or WildFly for that.
If you use JDBC direct from the application without pooling you might include the driver in the EAP file and separate the class loading, a good starting point for the documentation is here JBossClassLoadingUseCases