Thanks for the question Rob, it made me think and realize i was going about it the wrong way. I had to go the way of a snippet for this to work since the email addresses need to be in a colon-separated string. I re-purposed the snippet from this post and altered to suit my needs.
Final result:
// Get the Email of the selected items as an Array<br />var emailArray = skuid.$.map(arguments[0].list.getSelectedItems(),function(item){ <br /><br /> return item.row.Email; <br /><br />});<br /><br />// Convert this array to a colon-separated String<br /><br />var emailString = emailArray.join(';');<br /><br />// Redirect to Send Email page,<br />// passing in the Contact Email string<br />window.location.href = "/_ui/core/email/author/EmailAuthor?rtype=003" + "&p24=" + "noreply@abc.com" + "&p5=" + emailString;
