On simultaneous primitive roots

Given finitely many non zero rational numbers which are not $pm1$, we prove, under the assumption of Hypothesis H of Schinzel, necessary and sufficient conditions for the existence of infinitely many primes modulo which all the given numbers are simultaneously primitive roots. A stronger result where the density of the primes in consideration was computed was proved under the assumption of the Generalized Riemann Hypothesis by K. Matthew in 1976.