If possible, I would like to create a different shapefile to represent each possible combination of merges. Since yesterday I exported my attribute table to Excel and have been creating several dissolve fields from the list of adjacent feature IDs.
E.g., if the data looks like
FID1 - FID2
0 - 1
1 - 2
2 - 4
5 - 4
3 - 6
7 - 6
(+ a couple thousand rows)
I have a "dissolve_a" table that takes all the first appearances of each FID:
FID - diss_a
0 - A
1 - A
2 - B
4 - B
3 - C
6 - C
And a "dissolve_b" table that resolves all the first appearances of each FID after the FIDs for "dissolve_a" are removed:
FID - diss_b
1 - A
2 - A
5 - B
4 - B
7 - C
6 - C
And many additional "dissolve_" tables resolving the subsequent appearances of each FID. And you're right, there are many thousands of combinations!
Eventually I think I'll join each of the dissolve tables to the original shapefile, and then dissolve on each of the joined fields, creating several shapefiles of paired-off polygons. Unless there's something I'm missing? An easier way to do it?