Yeah.... you need to break up the media. In red cine-x for example, you could trim the clip to just the parts you need. Make a new clip with it. Then manually add that in to your session.
Another work around would be to set it to the lower ISO and then grade the other shots with a local version to raise the gain and adjust accordingly. Will also probably need some noise reduction.
But the red decode settings are universal for now. Not version based. Sorry I misinterpreted your question.
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