The drive can put out a maximum of 7A and 80V, which would work out to 80V and 3.5A per motor. Also, our drives have mid-band resonance compensation, which senses the rate of load change and is applied as a correction. If you have two motors on one drive, it does not know which motor to correct for. One motor would pump the other into resonance and would stall.
If your speeds are less than 3 RPS or less, you can run more than one motor per drive. However, that is only 180 RPM, which is something that will probably be too low.