[BrendanB]

There aren't rules in FIRST that prohibit you from participating on a different team.

The only restrictions would be by the school district. Some schools have rules prohibiting students from other districts participating in school activities but that is dependent on how connected your school is to the team.

When I was a student my high school had a FIRST team but I joined a local area team of homeschoolers and public schoolers whose schools didn't have FIRST teams.