We are adding a new type of publisher, called "MultiPublisher", see ECA-7337.

A very shortened description of the new MultiPublisher type: It lets you have "groups" of publishers, and select one or more publishers in each group. For each group, it publishes to a random publisher in the group.

The Edit Publisher page is able to change layout depending on the publisher type. These layouts are implemented as JSP fragments, for example "ldappublisherpage.jspf". We need a new layout for the MultiPublisher.

Since this is an old JSP page which won't let us do AJAX or page reloads, I suggest that we only have to controls for the MultiPublisher (for 6.15.1 at least):
1. list of all available publisher names as text, one per line (can be copy pasted from)
2. a text box where you can put publisher names. One per line, and a blank line to separate groups.
See the attached mockup.