No, participants must join their team through the Goosechase mobile app. As the Experience creator, you cannot assign participants to a team via the Studio.
How can I ensure participants join the right team?
To help participants join the right team, provide them with their team name and passcode (if enabled) along with instructions for finding your Experience.
Helpful honk: To save time, creators running large Experiences often choose to share a list of their participants' names along with their team name and passcode in a spreadsheet. They then distribute that list to participants along with the instructions for joining the Experience.