Different instance types for different workflow steps?

Is it possible to have different steps in a workflow run on different instance types? Or is it always just the single instance type?

I have a pipeline that contains some single threaded steps, like biobambam bamtofastq, and some that are multithreaded, like bowtie2 and samtools sort. Seems like a waste of resources to run a c4.2xlarge for a single thread. And a bit more cumbersome to have to run the pipeline in different steps and manually cleanup.