[galaxy-dev] Custom tool with multiple inputs for different datasets. How to preferrentially select

Next question - My custom tool take as input mulitple datasets from different tools and collates all the information. For instance, 1 input as tabular input, sampleManifest, another input is also tabular, expressionData. When the tool is display, both entries default to the most recent tabular dataset in the history. Is there a way to have Galaxy try to guess which dataset to default to as input instead of always choosing the latest input for all the fields?