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Here's how to set up or join a Group - first, make sure you're logged into your account at RunSignUp, and then choose the Tip To Tip event from your Races menu. Then, scroll down to the bottom of the page, where you should see several words that are actually links to activities. Look for the word 'Groups', and click on it:
Next, you should see a screen that has the following choices on it - and you should either choose 'Join A Group' or 'Create A Group'. If you create a group, please choose a name that will pass the censorship board ;-). Once you create a group, you should then contact anyone you want to join that group and tell them to follow this process but choose the 'Join A Group' choice at this point. You should then have a Group!