Can two different pairs of RSA key have the same modulus? Can $n=pq$ be part of two different pairs of RSA keys?

If such keys exist, say $(e_1,n)$ and $(e_2,n)$, how are they related? 
What will be the security concerns for the two users?
The users will be able to read each other's messages (even though they can have different private keys, say $d_1$ and $d_2$). This is because knowledge of $d_i$ is sufficient to factor $N$, thus allowing that party to compute the other party's private key. This was detailed by Boneh in his analysis of RSA attacks.