I did make the backup before trying this, which is good, because it didn't work out right.
I have my main family file (uds) and there are two people in it (father and daughter) who are also in the gedcom I am trying to merge/import into it.
So I open my uds file, import gedcom and it imports everything, except that the individuals in the original file are not connected to the individuals in the merged file. In other words, I fear they are dreaded zombies.
How can I get the new file to "attach" to my main file?