I am not sure I understand the question. If you put conductors associated with two or more circuits in the same conduit, they can share a single EGC, so long as that one EGC is sized for the highest rated circuit. But if you are asking whether a #2 EGC is big enough for the circuits in your question, we can't answer that without knowing the circuit breaker rating (this is the basis for sizing the EGC) and the minimum required ampacity of the conductors (this will tell us whether the conductors were upsized, which would require the EGC to also be upsized - per the code article that Don cited).