Feature: Require a specific user meta field value to be included in directory

[kimcoleman]

Some sites have a single membership level but want to create multiple instances of the directory based on a common meta field.

For example, a sports league may have a single membership level called "League Member" and have a Register Helper field that the member selects their "Team". They would want to create separate directories for each "Team" user meta value.

The same could be true of a State-wide organization that has user-selected "Chapters".

[kimcoleman]

See this recipe: https://gist.github.com/greathmaster/e0940b4b0cabb2130ace2568f995bba1