Can we decide which VOD Channel should be used for advertising on another VOD Channel?

Yes, you can specify which one of your VOD Channel should be used as Ad-Serving-Channel(s). Those VOD Channels will become your ad-source and all videos you assign to your Ad-Serving-Channel(s) will randomly be served to the publishing properties on which the respective ad-feed (from your selected “Ad-Serving Channel”) has been integrated.