I agree, you can. It won't be easy at times, but it will be do'able. I hear the netcode for Q3 is good, and it's been tweaked(if I remember correctly). If you're only concerned with a 4 player(small) game that should help to. Stick to dedicated servers(they're usually the best) and of course those close to you. Maybe try and find friends or other people who also have 56K.
Host a game and you'll always have the lowest ping.
Good luck, have fun.
"When kissed by the sword of Vengeance
Your head lays there by your side"
"Oh people, know that you have commited great sins. If you ask me what proof I have for these words, I say it is because I am the punishment of God. If you had not commited great sins, God would not have sent a punishment like me upon you!"
Genghis Khan, 1220