Saudi Visa Number

Hi there, 

I am a South African citizen who accepted a job in Riyadh. I am due to leave my country in about 3 weeks time. I am travelling with a group of individuals who are going to the same place of employments. This past week our visa agent sent us an update of the processing of our documents. 

I noticed that my visa number is the same as another applicant travelling with me, while the rest of the group has different visa numbers. 

My question is, is it common to have one visa number represent more than one person or should every person have their own visa number?

I desperately need some light shed on this, because I have to pay the visa agent and then go biometrics at VFS this week. I simply want to know if my money is going to be wasted and if I'm being scammed. 

All the visa agent had to say about the duplicate visa number is that it is common practice for this to happen for people of the same nationality.