I suppose... Traditionally, though, "guilds" are reserved for medieval or even just olden timescales. For modern settings, it's rare for groups to call themselves "guilds" unless they're actually keeping some sort of long-running tradition alive. It really depends more how formal you want them to sound. If they're organized groups, modern terminology would sound slicker.
I can always break tradition then. xD
The more and more I think about other words to describe a group, the more unfitting it feels for me. Such as "League", league sounds too super-heroic thanks to Justice League. Group sounds like a public school student project, and team seems more sportsmanlike. Organization is probably a good alternative because I'm making this bounty hunter agency government authorized. But then I would have to call the master of the group, the Organization Leader instead of Organization Master. Idk.