Calendar Sharing Question

We have on-premise exchange 2013 SP1. We have a number of franchises that we would like to share a calendar with. So these users would be on the internet and we want them to access a shared calendar of ours (they do not have exchange or office 365). According to:

https://technet.microsoft.com/en-us/library/dd638083%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396

we need a sharing policy. However, when i follow:

https://technet.microsoft.com/en-us/library/jj657494(v=exchg.150).aspx

the only option is to enable a federated trust. There isn't an "individual" option under organization->sharing. How do you create a sharing policy in exchange 2013?