CSL - Sorting by First Author

Hello I am getting started with the CSL visual editor, and I have reached an endpoint. I am using a very specific bibliography, in which there are many articles coming from the same authors, but with changing order. Thus, when I try to sort them by author, they are sorted by the name of the first author, then the second, then the third, etc. And then, finally, by publication date. I'd like to have a reference style sorting references by first author, and then by publication date, forgetting about the rest of authors. Here an example of my problem: 8. Collis, C. M., Grammaticopoulos, G., Briton, J., Stokes, H. W., & Hall, R. M. (1993). Site-specific insertion of gene cassettes into integrons. Mol. Microbiol., 9(1), 41–52. 9. Collis, C. M., & Hall, R. M. (1992a). Gene cassettes from the insert region of integrons are excised as covalently closed circles. Mol. Microbiol., 6(19), 2875–85. 10. Collis, C. M., & Hall, R. M. (1992b). Site-specific deletion and rearrangement of integron insert genes catalyzed by the integron DNA integrase. J. Bacteriol., 174(5), 1574–85. Here you can see how 8 appears before 9 and 10, having the same first author but being published later. I've tried to sort them by first author (not all authors) and then date: in this example, order would be 9-10-8. Is it possible? Thank you for your attention Carles