Big danger of timing error, one driver high, one low.
You could connect them using 2-? ohm resistors from the output of each driver to limit fault current.
If you can make sure the switching timing and sequence are correct, then it should be OK. One of the driver might be loaded higher compared to other as two drivers, even both from the same IC, are never 100% identical.
Even you have same timing, the output voltages can be different and destructive on the loaded IC.
Better if you want a higher current, use a different IC or boost the current by using a power transistor or another highpower constant current sourcing IC.