At OP, you can manage multiples sites under a single account:
https://support.squarespace.com/hc/en-us/articles/205810458-Managing-multiple-sites
I don't mean to nitpick, but Brine and Pacific are two different template families.
https://support.squarespace.com/hc/en-us/articles/115005308187-What-s-my-site-s-template-and-version-#toc-templates-grouped-by-family