[galaxy-dev] Setting Output Type with different input types

I have a tool that takes two input files, Input1 - a file of varying format(interval/tabular/fasta etc) and Input2 - a text format file. If I set the output format="input" it always sets to the text format, regardless of the Input1s format- which is not good for workflows where the attribute setting cannot be automated. I want the output to be of format Input1 Is there any way to specify the output format to be Input1.format or equivalent? Cheers Dennis