(I am not familiar with the ubuntu installation procedure, but the basic idea of my answer is still the same)
I am unsure if you mean core ROS things (that are usually installed in /opt/ros/ during the make install step) or if you are talking about additional ROS packages you have placed in your home directory.
If it is core ROS (e.g. the transport framework, the command rosmake) then doing the make install and placing it in /opt/ros/ should solve the problem.
If it is the additional packages or if its absolutely necessary to install the core ROS packages in your home directory, I would think you could add the users to a specific group you create, then providing group read/write/execute (or whatever you want) permissions to all the files under your home ROS directory.
@Lorenz mentions about shared ROS packages and building becoming an issue. My assumption of what he means is that if the packages are rebuilt, then the compiled files, libraries, etc will not have the right permissions. To solve this, look into ACL's, which will allow new files created under a directory to have preset permissions. A link to another answer forum for how to use it is here:
http://serverfault.com/questions/349145/can-i-override-my-umask-using-acls-to-make-all-files-created-in-a-given-director
On Ubuntu 18, ROS Melodic I have the same problem. On the same machine I need to connect two different users and both of them to run ROS without interfering to each other.
Any new developments?