Copy widgets from main site to sidebar of all additional sites.

I will be setting up a couple of rotating ad spaces on my main multi-site blog, and I would like to either through a widget, or preferably copy them through code/hard code sidebar.php in a child theme, across the designated sites.

I can’t seem to find a plugin that will accomplish my 2 goals)

1) administer ads on the main site
2) copy those same ads across my multi-site network for specified sites (Note: I am making child themes for each site, so would be very open to hard coding the plugin into the sidebar of the specific child theme)

Thanks!