Well, if you can use the same location for them all, you can use Current Player instead of P1, P2, etc.. if you want them in different spots, you can just follow this silly example...
Only have to do this 6 times:
P1: Current Player bring atleast 1 men to P1Buy: Move MasterBuy to P1Buy
And so forth for all the players. Then, for every "buy" trigger (or whatever action you want to do multiple times in different areas), you can just do it for Force1 or players1-6 (same thing) and just have
Force1: Current player brings atleast 1 men to MasterBuy: create 1 unit at Temp, move all men for current player at MasterBuy to temp
Then, for each player, do 12 more easy triggers.
P1: current player brings atleast 1 BuyPerson to Temp: Move back to P1SelectorArea.
P1: current player brings atleast 1 men to Temp: Move to fighting area.
That way, you have 18 triggers doing busy work, but it allows you to only have to make 1 instead of 6 for every action you want to do from now on using that location. Yay.
Also, use the action Comment at the end of all your triggers, it is extremely useful for organization sake. Anything you write in comment only shows up in the editor.
As far as using a text trigger editor to allow you to make those changes easily, you need to use SCMDraft, which is (in most people's opinions) the best editor out there for SC maps.
http://www.stormcoast-fortress.net/cntt/software/scmdraft/I would recommend it, and it will in general make everything much easier for you
EDIT: People posted since I started writing
Note that I would recommend using Notepad++, Wordpad, anything really except Notepad because notepad is very inefficient and slow when it comes to doing searches and replaces in big text files.
None.