project structure question concerning dynamic reconfigure and the parameter server

I have a system with many nodes, some written in C++, and some in Python. When devising the original "block diagram" for the system, I defined a parameter `/operating_condition` that is basically like a system-wide global variable. It is just an integer value used to tell many of the nodes what the system is currently doing. Often in callbacks, I will poll the parameter server to get an updated value for this parameter, and then respond accordingly. I later found that as the number of nodes went up, and hence, the number of calls to the parameter server, I started getting large delays randomly cropping up. I eventually read on [this page](http://www.ros.org/wiki/roscpp/Overview/Parameter%20Server) that this was a bad idea, and I switched almost all of these calls to use `getParamCached()`. That fixed the problem, but it is clearly not quite the right solution, more of just a temporary fix. As the project has evolved, I have been forced into writing more and more Python nodes, and there is no equivalent to `getParamCached()` (see [this page](http://answers.ros.org/question/35262/getparamcached-in-rospy/)). Using the [dynamic_reconfigure](http://ros.org/wiki/dynamic_reconfigure) package doesn't seem quite right either. What is the right solution? A topic subscription with a callback in each node? Write my own service handler that can handle requests from each node? Just don't use "global" variables?