It makes enough sense that I think I can say your note will probably get ignored anyway and they will do what they want and how they want unless someone is consistent about checking on them and has some way of enforcing the procedure.
But, call it out in a separate detail and call it for 6" long backstepped welds, or whatever length you want them to be. You could even sequence the welds by numerical order putting '1' in one location, '2' diagonally opposite, '3' back over by '1' but backstepped into it not starting with where '1' ended.
Now, am I making sense? I am trying to think of where I have seen an example of this. I'm going to have to review some documents when time permits. Maybe someone else can give you better guidance.
Have a Great Day, Brent