Kevin,
In case you'd have to stick to the second option, you might be able to distinguish your values by session IDs (there is a function module named like TH_GET_SESSION_ID - I do not have a system right now to confirm the name). Another opportunity to determine to which session a particular value does belong to might be getting the process ID in case session ID won't work.
Regarding another opportunities - nothing different pops in my mind 
Cheers,
KS