Well, the poster here known as kelfar could sell you an ison machine.
No, no, no, don't do that. Ison machines are terrible and sound so artificial! A human ison is so much more desirable.
As far as your chanters go, if you have three chanters and two of them women, the male can supply the ison while the two female chanters provide the melody. It can really be quite sonorous. I understand that you are still learning, but Byzantine chant without an ison sounds, quite frankly, bad. I'd recommend that you learn holistically.