two-three-four (2char + 3char + 4char) combination

[Gyfer]

Suppose I have three wordlist files: 2.txt, 3.txt, and 4.txt. The file 2.txt contains 2-letter words like "my," "to," "is," and so on. The file 3.txt contains 3-letter words like "cat," "sun," "dog," and so on. Lastly, the file 4.txt contains 4-letter words.

how do I make a attack that will generate the word "ishashcat!" ??   ( is a  2words + 4 words + 3 words + single ?a )

Thanks !