Is it possible to have Kaito and Meiko's soundbanks on Vocaloid 2's interface?

If I have Kaito and Meiko they go to Vocaloid software. If I have Miku, Len, Rin, Luka, ect., they go to Vocaloid 2 software. How can I get them all to sing together? Do I have to redownload the voicebanks?