If you happen to be a member of 2 iOS developer teams you will most likely experience issues when attempting to sign your apps. The reason why you might experience it in the first place is if you are registerede with both a regular iOS developer program but also an Enterprise developer program. In that case it is most likely that you have the same name for the two teams.
The error you might see is the following
Code Sign error: Certificate identity 'iPhone Distribution: XXX TEAM NAME XXX' appears more than once in the keychain. The codesign tool requires there only be one.
To solve this issue you have 2 options, that both include a little work with the Mac keychain
1. You create 2 accounts on your mac and then you use one for developing for the App Store and the other for developing the enterprise apps.
2. You create 2 keychains store your keys in each their own keychain. That way you can remove one keychain at the time and then only have one set of keys active at any given time. That way you will not have any conflicts.