No it is not safe to keep the male and female hamsters together. They fight with each other most of the time and can also kill each other. They also eat their babies. Hamsters needs lot of attention and care.

 Slowly introduce others....don't force it ...also the animal senses your feelings so you should not be around when someone else is petting it or holding it....you may be the problem...in fact it may be that you want the situation to be....good luck