Xfinity stream active in multiple locations

I have three Xfinity tv accounts in three separate houses, for all of which I pay for a tv package.  There are people in each house and I expect that they should have access to Xfinity stream inside the houses.  However, nothing is ever easy with Comcast.  Xfinity stream will only play in whatever house I set as “primary” or “default.”   This makes me mental as I pay upwards of $200 for each account yet I am only able to stream on smart TVs in one at a time.  There has to be a fix for this (I state, not truly believing a simple solution exists). Any ideas?