Hi Jon,

There is servals ways how you could do this. One way is to add a macro parameter, to your macro, so when you add the macro to your template, then you can specify a id of a content node, and you will then be able to loop through  e.g children.

Another and more flexisble way is to use the bult-in Multinode treepicker which sounds to me is the thing you need. With this you can specify out items with specific type, set an start position, where is should be possible to pick items from. Setup and maximum or minimum numbers of items to pick. You can find the documentation for the Multinode Treepicker here: http://our.umbraco.org/documentation/using-umbraco/backoffice-overview/property-editors/Built-in-Property-Editors-v7/Multinode-Treepicker

The only thing you need to know is that the Multinode Treepicker data type is not by default under data types in the developer section. What you need to do is th create a new data type, give it a name, and then choose the Multinode Treepicker as the property editor.

After that then you can add it to a document type, as property, like you normally do.

Hope this helps, and make sense. Don't hesitate to ask more questions.

/Dennis