The Hollywood cast is rumored to be a part of iO, a west-coast based version of iO Chicago, an improvisational comedy troupe. Since this season is the season of aspiring actors, musicians, models, etc., it would make sense to give them a job like this, where the roommates are learning to be entertainers/performers.
You can check out the website here. Rumor has it they have had a show already, but it seems like no reference to any of the castmembers being a part of iO is made on their website.
Greg (Hollywood) apparently missed one of the comedy shows in order to attend LA Fashion Week sometime ago. He was then let go from the cast.