The journal does not contain the line of code (imagine needing to log that information for every single global modification), so to find the relevant code would require the type of cross referencing I suggested. The other option I would suggest would be to go through the program in the debugger. Especially if you have a general sense of where the relevant change would be made. But again, maybe the best option depends on why you are looking for this specific global set.
Most likely more context on what you are trying to look up would be helpful to understand how best to approach this request. What occurs to me immediately is this might be a good case for involving the WRC to help investigate.
If you want to look into it yourself I think you would want to read through the journals to find the global set in question and what is being done around that set, then tracking from the process to what else it was doing at the time. You may need to have a SystemCheck / irisstat running in order to correlate the process to whatever routine it was running.
I would generally caution against killing IRIS jobs from outside IRIS, as under rare conditions this could lead to IRIS hanging. If this is a concern I would suggest reaching out to WRC who can help you confirm that a process is safe to terminate.