Chow (1960) test of equality of coefficients between 2 outcomes

#1
Dear statisticians!

I have a question about using Chow tests (1960) to test the equality of coefficients for the relationship between a predictor and 2 outcomes. As far as I understood from the Chow (1960) paper, it actually seems to test the equality of coefficients across different groups…not 2 different outcomes. Yet, I have this paper Wyatt & Silvester (2018) that uses that test for equality across 2 outcomes. I wrote to the authors but they haven't replied yet…

Basically, my question is how do you perform this Chow test in order to test the equality of coefficients between 2 outcomes?

Thank you SO much!
Margarida