I have a FeatureClass derived from ArcGIS Desktop 10.6.1's Polygon Neighbors tool [Windows 10 - 64]. I have supplied a tiny sample (of >250k) that gives the flavour and an example of the objective.
The attribute table is sorted by area - so we start with the smallest polygons and work our way incrementally through progressively larger features (there will be a cut-off beyond which I'll not want to progress - but let's not worry about that at this stage). In this example, we stop at OBJECTID = 7.
The attribute table includes fields src_OBJECTID and nbr_OBJECTID, generated originally by the Polygon Neighbours tool. I have dropped all neighbours other than the single feature with which the feature src_OBJECTID shares the longest boundary (attribute = Maximum_LENGTH).
What I am wanting to do is to dissolve progressively larger src_OBJECTIDs into their nbr_OBJECTID.
So, for example, the smallest polygon (src_OBJECTID '388') has nbr_OBJECTID '668'.
668 is thereby identified as the (longest shared boundary) neighbour of 388. 668 is also a (larger) SOURCE polygon feature further down in the table, with src_OBJECTID 668.
So I need do dissolve feature src_OBJECTID 388 into that neighbour feature - src_OBJECTID 668.
I then increment to the second-smallest feature. This is feature src_OBJECTID 131, which has to dissolve into its largest neighbour - feature src_OBJECTID 459. You will note that the third feature (OBJECTID = 3) is src_OBJECTID 459, and this has to be dissolved in turn into feature src_OBJECTID 668. So this is an example of nested dissolves, which are very common in the full dataset.
The subsequent features all dissolve into src_OBJECTID 668.
The difficulty I'm having is that I do not see how to select the target for the dissolve on the basis of it having the same src_OBJECTID as the nbr_OBJECTID of the fragment being dissolved into it.
Or, as @Hornbydd put it much more clearly:
... how to dissolve all the nested polygons, so in your example 131 dissolves into 459 which dissolves into 668 as well as all those that dissolve directly into 668 which ultimately dissolves into 638?
I'll create an image tomorrow.
I am stuck at the first hurdle (no ModelBuilder stuff to show). I would first of all like to establish whether this is actually possible.
Then, if it is possible, establish the sequence of ArcGIS Pro tools required.