After having inserted JabRef citations and merged them, how do I reorder them without starting all over again?

I have inserted citations in a libreoffice (5.0.6.2) writer document with JabRef (3.7) and merged adjacent citations (“Merge citations” button in JabRef), let’s say, creating the citations [1-3]. Now I want to add another reference, which should be reference 2. However, adding the citation and pressing merge, I end up with the new reference getting number 4 and not the desired number 2. Is there a way to reorder the merged citations without deleting everything and starting all over again?