I am using DNAGedcom to gather all of the ahnentafel trees from my DNA matches then I use DB SQLite browser to export the ancestry_matchTrees table. I open it with charting companion then I end up with a gedcom. The current file that I imported into rmgc file has about 800000 people in it and 13000 trees. I want to be able to upload my dna matches file to RM, so Rootsmagic can use the DNA Kit fact charting companion makes in the gedcom for each root persons and the DNA matches file that also has that same DNA kit number to look up the shared cMs, so the trees can be selected by the number of shared cMs. This allows me to prioritize which trees I research first and leaves me less worried about appending the file, because I finished working on the trees in the file. (I could import less trees by not grabbing all of them by limiting the cM range when grabbing trees with DNAgedcom). Let me explain how I am using this file. I am making a new empty file and dragging and dropping the descendants and their spouses of a most recent common ancestor. If I want to add their ancestors I may drag and drop them too. So then I color code the tree for that person, so I am not trying ot assign it a most recent common ancestor when I already have assigned it. I navigate to the root person that has the DNA kit ID and assign all ancestors green then I navigate to the most recent common ancestor and assign their ancestors and descendants and spouses red. This way I know my biological line and can see how to add others to my biological line more quickly by scrolling through the list of DNA matches. Oh, I forgot to mention to speed up the process I am assigning groups for my ancestors using ahnentafel number then their last, first name for all ancestors going back 6 generations in hopes that my ancestors are indeed my biological ancestors. This alos makes it easy to see my DNA matches guesses to their ancestors very quickly coupled with web hints it helps me research my line faster given that some of those hints are correct. Now the issue. I just put a ton of work into the file of 800,000 people and I don't want to update it with lets say a file of 900,000 people to just start from scratch. Is there a way to use ids of ancestors or something similar to allow me to just append to my new file the information that is missing. I need them to append to the correct trees, but I will be using a new DNAGedcom csv file to have charting companion to make a completely new gedcom that I need to use to append the rmgc file that has 800000 people and tons of work. As long as I don't make any fact changes in the 800,000 people file other than groups and color coding would it be possible to just append the file? We have to remember that new trees are being added to DNA kits that never had a tree added before and new people are testing and attaching trees, Then you have those doing research and changing their trees. I think the problem needs to be solved by sites and tools sharing and tracking ids. I understand RM already tries to do some of this, but I don't think you have a solution to my problem, but I could be wrong.