That is not a solution. The assert is there for a reason, and you’re essentially running into motoman/#91.
Looking at the output in your previous post, it appears you’ve duplicated group 2, that won’t work. Your robot has either 2 or 3 groups, and the motion_interface.yaml should reflect that.
The configuration that @andreaskoepf posted would be more like what you should be using, but then we’d have to fix motoman/#91.
If @ted-miller could clarify whether the approach used by @andreaskoepf is acceptable / supported, you could even use that configuration and the MotoPlus changes. But let’s wait for his comments.