There is no limit to the number of teams you can be on in the TeamLinkt app. As long as you are being added to the rosters with the same email address, you can toggle between multiple teams in the app.
From the app:
Open the TeamLinkt app
Click the team name or the down arrow icon in the top left
From here, you will see a list of all the teams you are added to. Select a different one from the list to view the additional team.