[galaxy-dev] Multiple inputs in a workflow (variable number of inputs) ?

Hello, The number of inputs is not fixed for my workflow, maybe I have 6 inputs, maybe more than that, the number of inputs depends on what data I have for the analysis. As I know, in a workflow, all inputs should be pre-defined...that is to say, the number of inputs is known before running one workflow. Do you have any idea for this problem? How can I do to make a workflow with the variable number of inputs? In advance, thanks for the answer, Yufei