Series of SF short stories parallel universe travel company disaster strands people in infinte corri

I read several of these in Asimov's Science Fiction Magazine during the George Scithers years, so late 70s or very early 80s. The basic premise involved a company that let you take vacations in parallel universes (I think, it might have been researchers, but I don't think so) when there was some sort of breakdown in the system. People were still able to get out of the places they were in, but couldn't get back to their home universe anymore. Rather than traveling straight back they found themselves in an infinite corridor with doors leading to the different universes. At least one story involved a group was either military or company security or something like that gathering people up and trying to find their way back home. I thought the author might have been John M. Ford, but I haven't been able to track down any of his stories that sound right. Certainly it was from around the time he was starting to make a name for himself. Just the author's name would be a big help, but some story titles would be nice too.

Yes, it's Ford. These are the "Alternities, Inc." stories; they include "Mandalay" and "Intersections", which are collected in From the End of the Twentieth Century.

Thanks! That's been bugging me for a while, but I always forget when I'm near a computer. I think I had Alternities somewhere in my head, but figured I was confusing it with the Michael P. Kube-McDowell novel. Which may explain why I bought the McDowell book in the first place.