About a year ago TUG separated out many TS systems to their own boards thereby creating the Hilton, Starwood, Disney & Wyndham boards.
TUG has not seen a need for a separate Hyatt board because there doesn't seem to be enough demand for it. This may change if there was enough of an outcry from the members. Although Hyatt has about 1/4 of the posts on this "other TS systems" board. Diamond /Sunterra also has a lot of posts on this board.