Random Name picker based on 2 conditions

Hi,

I am trying to create a spreadsheet that will randomly pick a name based on criterions.
I have names in Column A, Subject in Column B and KS3 0r KS4 in Column C. I want to randomly pick a name from a student from each subject and each KS. For example, pick a random student from English in KS4.
So far I have something that s the long way round and their must be a simpler way as if I continue this way then it will take some time.
I think I need to do INDEX and MATCH but I am not an expert on these and needs some guidance.
I will upload what we have done so far.