These are my 3 suggestions, since this obviously isn't an easy answer!:
(1) Ask the server if it would be a pain to ask for separate checks, and if he/she is fine with it, go for it. If they say it's a problem, then see #2 or #3.
(2) Designate one person as the "money person" for the entire trip. There's usually at least one in every group who is good at figuring out the money stuff. For my group, that's me (I went on a group trip with 6-8 people, and it was my job to figure out anything relating to money).
This money person should be armed with a pen, calculator, and a piece of paper. When the bill comes, write down everyone's names on the paper (you could even pre-print these at home with the names and spaces to put amounts), and all the items that belong to them. While you're doing this, check them off the tab so you know which ones you counted already. Deteremine with everyone ahead of time how much tip you're willing to pay. Let's just say it's 20% and tax is 7%. You would multiply each person's tab by 1.27 or 27% if your calculator has that feature. You can write down what each person gave if they don't have exact change, and work the change out later.
(3) If you determine ahead of time that a lot of people in your group don't want to bring so much cash for meals, you can rotate who pays for what with credit cards. Again, designate one person to keep track of all of this. Create a simliar chart to #2, so you know how much each person is eating each meal. On day 1, person A can charge lunch and person B can charge dinner, and rotate. Every night, have a running tally of each person's meal total, and subtract out what they charged. So if person A ate $40 of food but charged $120 for one of the meals, they have an $80 "credit." At the end of the trip, you would need to do some calculating. The "debits" and "credits" should be almost the same amount (they should be exactly the same, but no one's perfect!), and the people who have debits owe the people who have credits.
I agree that splitting things evenly can cause problems in the long run -- I'm not even thinking about me losing out, I would be afraid that my friends would lose out!
Anyway, whoever said there is no easy solution is right, but with proper planning, and at least one person who is willing to be the "money person," I think you can do it.
Oh, and I'll throw in a 4th option: again, a designated money person, can collect say, $200 per person, in advance, and will be in charge of keeping track of everyone's meals. Periodically, see how much of the $200 they've used, and they can "recharge" their credit by giving you more money. Make sure you've always got more, rather than them having to owe you money. At the end of the trip, give back whatever "credit" they have left. Then there's no fussing at the table with money going back and forth. The person with the money envelope pays, and if you get a copy of the tab, you can do the calculations later.