An Air Carrier Captain reported a near collision during taxi at ORD; averted only when an alert Controller shouted for him to stop.

Narrative

On taxi out Ground gave us taxi instructions of 32L at T10; Taxiway H; A7; T for T10. When I was approaching where H splits into A and B; I had my First Officer ask Ground if he wanted us to take A or B to A7; to which he replied B. I started accelerating onto B with moderate Ground radio calls when the Ground Controller yelled on the frequency 'Stop!' Not knowing [who] he was referring to; I immediately stopped the aircraft just as my First Officer said 'Stop; there is an airplane!' An [aircraft] had landed 27L and was exiting at the high speed A1; which goes right into B. We were on the parallel taxiway; with the aircraft coming from behind us where we could not see it. The wingtip of the [other aircraft] cleared our nose by less than 15 feet. Had the Ground Controller not been paying close attention; we would have continued taxiing; probably into the path of the [other aircraft]. Since there was no way we could see the [other aircraft] from our position; we were relying on the controllers to ensure that our taxi path was clear. At no time was any mention made of aircraft landing 27L. Perhaps better communication between the Local and Ground Controller as to exiting aircraft; or hold short requirements for Taxiway A1 at ORD when landing 27L. To pass this intersection going west [should] require a specific clearance.