I've seen and heard of this only once, and it was a new breeder who only tried/did it once.. only one female ended up breeding with the male, and the other female kept interrupting the process, causing undue stress to the breeding pair as they always had to stop to chase away the other female.
The only other way I have seen is someone able to release a second female immediately after the first pair bred, but that is also a rare thing.
Either of those is not recommended unless very experienced and know how to do it properly to ensure safety of all fish. But even the most experienced don't even try it - why I've only run across it once and with someone who isn't a big breeder.
So technically, it could happen, but realistically it isn't a good idea.