Grow from seeds - limit to some segmentations, no overlap


I’ve been using ‘grow from seeds’ successfully for some cases. I do understand it requires at least two segments to run (foreground + background).
However I have a case, where I would like to use a 3rd segmentation as an additional boundary for the segmentation.

The context is that I have Left Atrium that is segmented to some extent and I would like to expand it to cover more of PV. So I load the initial segmentation, put some seeds in the uncovered part of the organ, draw some background and…

Now I would like to run ‘grow from seeds’ only on those two new segments, with the setting ‘editable area’ == outside all visible segments.
But this is as well growing my initial segmentation, and I don’t want it, because it is not a good source of seeds, it has some over-segmentations here and there.

I managed to move the original segmentation to another segmentation node, which excludes it from being used in ‘grow from seeds’. Is there another way to achieve that?

However - as one can see on the screenshot it didn’t fully stop at my other segmentation - they do overlap:

I understand I can now run other operations to get what I need, I just wonder if this the best way I’m doing it?

You can only make autoupdates to your grow from seed process if you have saved it in a “non-applied” state before.
As soon as you “Apply” changes via Grow from seeds changes to the original are not possible.

Yes, I get the difference between ‘unsaved’ and ‘saved’ state of ‘grow from seeds’.

My concern here was that even though I selected ‘editable area’ == ‘outside all visible segments.’ → the growed segmentation overlapped with another visible segment, and this is something I don’t want.