Is It Possible to Import Multiple Streams as a Single Clip That Expands into Stacked Layers in PR

Hello Adobe Community,

I am currently developing an Importer using the Premiere Pro SDK.

The goal of the importer I am working on is to function purely as a dummy clip.
When a file is dropped onto the timeline from a CEP panel, the Project panel, or Windows Explorer, it should only store the start time and duration and then be removed.
In other words, the clip itself does not represent actual media.

The behavior of the Premiere Composer importer plugin matches exactly what I am aiming to achieve.

At the moment, I have successfully implemented importing as a single clip, and this works as expected.
However, I have been unable to implement the behavior where multiple streams are recognized as a single clip, but when dropped onto the timeline, they are expanded into a stacked, layered structure.

To be honest, I am not even certain whether this kind of behavior is achievable at the Importer API level.

I have already spent a significant amount of time working on importer development, but unfortunately, I have made no real progress on this issue.

If there are any experienced or knowledgeable developers here, I would sincerely appreciate your guidance on how this might be solved.

Below is a summary of what I have observed so far.

When GetInfo8 returns imIterateStreams and I advertise the existence of multiple streams to the host,
Premiere places them into the Bin as a single clip.

When I assign a streamName to each stream,
Premiere places them into the Bin as two separate streams.

I would like to try labeling streams using imQueryStreamLabel,
but this selector has never been called, and I have no understanding of under what conditions it is triggered.
It has never been invoked so far.

When I set streamsAsComp to true,
Premiere loads a sequence and one clip with two streams into the Bin,
and within the sequence, the streams are expanded and stacked.

The behavior also changes depending on whether the streams share the same metadata or not.

This is the closest I have come to a positive result, since the streams are at least stacked inside a sequence.
However, because they are contained within a sequence in the Bin,
the file cannot be dropped directly onto the timeline, which defeats the purpose.

I have tried many other approaches as well,
but I have not been able to achieve the desired result.

No matter what I do,
I cannot seem to implement an importer that is recognized as a single clip
and expands into stacked layers when dropped onto the timeline.

Is there any known solution, workaround, or even a hint
that could point me in the right direction?

Was this functionality implemented through an unofficial approach,
or possibly reverse engineering?

I am truly desperate for help.
This feature is something I really need to implement.

Thank you very much for your time and consideration.