If you turn osv into a string_array resource, you can create combined types. You can set osv on the RHEL6 machine to resources_available.osv=R60,R60_R65
You can set it on the RHEL6.5 machine to resources_available.osv=R65,R60_R65.
When someone wants R60 or R65, they request it. If they want either or, they request R60_R65.
@adarsh is correct, we are in the process creating a more generic specification that you can make requests with boolean logic. Until we finish that, this trick with the string array should help
Bhroam