That's not how facing worked in AD&D. Remember, no grid combat - this was string and ruler territory. Your front face, or arc, was basically 120 degrees in front of you, meaning you could attack at least 3 targets in front of you, and, arguably you could attack the target to either side of you as well. Directly behind might be an issue.
However, again, because of the 1 minute rounds, facing wasn't really an issue. You shield was effective vs a set number of attacks, regardless, really, of location for example. There was no, "I run around behind him and attack". It didn't work like that. So, yes, you could certainly attack multiple targets around you.