I have a Blackberry 8700g with my company BES mail going into it via the company service book CMIME. Another service book CMIME for O2 mail and then the full service suite connected to my home account via mailstreet syncing Tasks,Calender Memos and again messaging CMIME.
So I have two BES servers and O2 internet mail connected to one blackberry. When first activating the BB to each BES server delete the service books you dont want.
When sending out mail the compose E-mail gives me three choices. O2, Company or Mailstreet.
So it is possible to connect two BES Servers to one Blackberry.It works a treat.
Curtis