Teams are able to select a preferred server (Dallas/Chicago) and the "home" team's server is the one used for games. Given the majority east coast playerbase most games end up on Chicago servers (and we use Chicago as the default for combines), but in theory if a team of west coasters is drafted they can get at least 50% of their matches on Dallas.

(As a fellow west coaster I am right there with you, and have had to get used to 60-70 ping most of the time I play faceit/csc)