Hi Joe,
A microflow can never receive a primitive string from a widgets (not for dojo not form pluggable widget), only microflows calling microflows from an other (sub)microflow or nanoflow (since 8.8) can pass a string.
In widgets, you can provide a context objects (including the parent) to the microflow. You should store your string data in one of it attributes.
In your case you could create an attribute property https://docs.mendix.com/apidocs-mxsdk/apidocs/property-types-pluggable-widgets#attribute And set it on click with a string (or enum) value of you section, and process all your request with a single microflow.
Cheers, Andries