This is definitely possible as Confluence does support things like iFrames etc. Here is an article on their website that talks you through the steps of creating an Fram to embed content from another source: https://confluence.atlassian.com/confkb/how-to-put-an-iframe-into-confluence-598837531.html
Once the iFrame has been created and included, you can use the minimode links for the processes you wish to embed in Confluence to expose the processes you would like to share. This does not have to be done in an iFrame, if Confluence supports other methods of embedding the content then those could be explored too (as per the image below):
Hi there, we initially tried to embed Promapp into our Confluence intranet, using iFrames, but it wasn't exactly straight forward. What we have done instead, is create a series of easy to read pages, that steps through all the information the end user might need without needing to log in to promapp, with different formats, using minimode links to the process instead. I've attached an example of what it looks like. The feedback we've had so far has been really positive - it caters for those who are visual & like to look at a map or browse online, versus those who prefer to read a document. We also give a quick guide/cheat sheet "key info on a page" for the key parts - less detail if they just need a refresher.
I hope that helps, Trace