Holy wow, HolyDuck ... that did the trick. If you have an existing window open with a specific tab group, one that is named/setup ... clicking any link in another app will launch an entirely new window, and place it on the left most opened desktop.
But, as you said, if you go to the group tab pull down (upper left corner) and use the first one (not one of your specified tab groups) ... clicking links in other apps will launch them in that existing window, but in that unnamed / non specified tab space. Brilliant!
I guess, it's forcing another window rather than adding a tab to a designated group, or switching from that group that is open back to the initial / general area. Kinda makes sense I guess, but hard to figure out why ... thanks for the insight!