Just a note re Djungarian hamsters, unlike other hamsters they are social and can be kept in social groups, though they do reproduce readily so attention must be paid to gender…although nocturnal, they are also active for brief periods during the day.
Sounds like appropriately sexed gerbils may do it for you, Jive…but a slightly larger cage might get you a guinea pig or rat, more companion for the space!
Most rodents, it is not that difficult to determine sex. Just look closely, feel, etc.