NicheActionPager

This addon allows the default UI's extra action bars (MultiBarBottomLeft, MultiBarBottomRight,
MultiBarLeft, and MultiBarRight) to change pages with the main action bar. This functionality
can be enabled or disabled on each bar, and the action number offset for each can also be
customized. The "/nicheap" slash command can be used to accomplish this.

For more information, including version history, support information, and other such details, view the
addon's home page here.
However, please download from WoW-Interface if possible, to save my limited bandwidth.