How to suggest a new word from two correct ones

[behradbv]

In many languages like English, there are numerous compound words e.g. football which consists of two separate words with separate meanings.
In this example, I'm looking for a syntax in Hunspell, when the words "foot" and "ball" are next to each other, the Hunspell suggests the word "football". When I was browsing on the web I came across a command that acts in reverse:
REP 1
REP onetwothree one_two_three

But unfortunately it was not able to do what I expect.