Split string from one field from input to three or mutiple in output

I'm battling to achieve something which in my mind should be simple.

I've got a string in a field from the input plugin like this:
bigfield:"something - something1 - something2"

I need to grok or mutate it or something else by splitting on the "-" character so that I can send three fields to the output like this:

I've looked around for a similar problem, and perhaps I'm just describing it wrong - but I'm having no luck getting an answer for this.

Does anyone have any ideas?

Look at the csv filter.

It can use any separator characters not just commas - but not regular expressions.