This is not possible I'm afraid. You have to use extended attribute filter if you want to filter on specific node ids. I don't know details behind your implementation logic, but it might be also possible to use offset and max params for foreach template function if you want to skip some first nodes in second loop. Then only one fetch could be used.
I was able to use the offset method in a couple tpl locations but we also have an eZ Flow zone with 2 dynamic blocks that could benefit from this. Both blocks use eZFlowLatestObjects -- same class and parent; just a different number of active results.
What about writing a custom template function optimized for your fetch? That also enables you to tune the query for your situation and optimize for memory usage and performance.
