Try this...
  !server server1
  !server -m server2
  !server -m server3

ON *:CONNECT:!autojoin -d5

Then use the Favorites channels list to pick and choose which channels to join on each server. There will be a five second delay after connecting, which should give NickServ time to recognize you so that your channel joins will work properly. Will also reduce the risk of the server detecting you as a flooder and kicking you off.