There are a couple of options that will get you to the place you want to be.
1. Go on-line from a PC and log into you gmail account. Group each entry into whichever groups you want (you can tag a contact with multiple groups.) Download an app (I'm sure there are others) called Contact GroupU from the Market (its free I believe.) Then you can use that to wade through your contacts by group.
2. If you are just wanting to be able to find a particular contact to call without searching through them all, you could use something like Dialer One. I can't remember if its free or not, but I wouldn't use my phone without it. From the dialer pad, you can enter numbers or names and it displays contacts that match what you've entered. Once you get to the contact and tap them, you get a menu with your various email, phone and sms options listed. So if you wanted to text Arnold Swartzenager, you would open Dialer One and on the keypad enter 79278(SWART) and on the display you would see good ole Arney's name listed. Tap his name and you get a menu of "communication" options. Tap the icon for your texting app and your're off to texting.
I use both of the above options. If I have to mass send stuff, I use GroupU. Once you open the group, you can selectively pick the recipients or do menu>select all to hit all of them. I use Dialer One for all other communications. If I want to text someone, I open Dialer One, start typing their last name and when it pops up I tap it. I get a menu of options.
I think by now, you get the drift.
Good luck
BigRedGonzo