I appreciate the suggestion.
And yes, I can do it this way.
The complications are (I consider them complications at least) are the following:
a) Even one one selects a specific subsector, ALL the data of the Spinward Marches remains in the Sector Data window.
b) The systems are listed in Hex Number Sector format, running down the length of each row of hex of the map, one subsector after another. When it reaches the bottom most planet in the first row of the sector, the listing goes over one row, and goes down the second row through many subsectors, till it reaches the bottom most world of the sector's second hex row. Repeat.
This means hunting down each world separately, making the changes, and then hunting down the next world. And while this is more than feasible, I was hoping for something more blunt.
Please, don't anyone take this as me complaining about the Traveller Map. IT'S AMAZING! I'm trying to make it do something it wasn't designed to do, and something most people would never think of doing. So it's all on me.
Just wanted to know if there was a way of doing this better than a hunt-and-peck method -- specifically because I was interested in having a map printed of the whole Gamma Quadrant addressing the issues I mentioned above.