Editing global files

In modding 2K, I often notice that modders release certain mods in a global.iff file
Problem is, that just replaces the global I already have which may have things I want to keep.
I've read as much as I can around the forum, and see people talking about importing into a global file with 7zip.
Can anybody help me out with that? I'm not understanding it, because when I open each global file with 7 zip, they are the exact same files and would still just overwrite if I did it that way.

What I do is combine multiple globals together.
I use the chinese global as a base, and if you sort the files by modified, the files that have been change should be at the top of the list.

phpBB [video]

So next I pick and choose from files from the other globals that I want to use. For example, I use Lagoa's sweat global. So I open it up sort the files by modified, and I drag the files that control the sweat to the chinese global.

phpBB [video]

You can combine as many global files as you want by doing this. Once you're finished you just throw your combined global into your modded folder.

This is a handy tutorial -- thanks for taking the time to explain.

What I do is combine multiple globals together.
I use the chinese global as a base, and if you sort the files by modified, the files that have been change should be at the top of the list.

phpBB [video]

So next I pick and choose from files from the other globals that I want to use. For example, I use Lagoa's sweat global. So I open it up sort the files by modified, and I drag the files that control the sweat to the chinese global.

phpBB [video]

You can combine as many global files as you want by doing this. Once you're finished you just throw your combined global into your modded folder.

Thanks so much for this