I will… for the most part. You bring the authors and books and make those books 99c or free, and I’ll make and maintain the landing page, create graphics, and do whatever else I can, including trying to find more authors to fill up the page. The more authors, the more successful the cross-promotion can be.
However, each author is responsible for promoting the cross-promo’s landing page to their social media, news letters, and Facebook Groups the day before and all during the promotion. However, personal / virtual assistants can do this for the authors. So if you really don’t have time, consider spending a few dollars for a PA/VA for those few days, or finding someone who loves you enough (and who you trust enough) to do it for free.