Two Amps into One 4x12 - Possible?

[Searcher]

Would it be possible to run my guitar into an A/B box, then from there send two leads out to two different amps, and then send them into the same 4x12 cab?  Obviously I'd need something to combine the two speaker leads into the one input of the 4x12.  Since the A/B box would only allow one amp at a time to drive the cab it seems like it would work, but I don't know if I'm missing anything here.

Thanks.

[hunter]

That's probably going to create problems. Your solution exists though, it's called Headbone and is available through ebay for around 150 EURs (I own one which I bought off ebay for 140)
http://www.tonebone.com/tb-headbone-vt.htm

The important thing is that it puts a dummy load to the inactive head.

There is one drawback: You cannot have delays or reverbs active in the loop when switching an amp off, as the remaining signal would kill the dummy load (which is only designed for a quiet amp). So you either have to be careful and always switch those off when switching amps or you make sure delays etc are only before the headbone...

[Searcher]

Ah, right.  I knew there was something that was slipping my mind.  Cheers.

[JamesHealey]

can you put a hotplate between that thing and the speaker cab?

so you kinda got..

Amp 1  -> A -> Amp Dummy Loaded
Amp 2  -> B -> Amp Selected -> Hot Plate -> Speaker

[Skybone]

You could try running the 4x12 in stereo mode, so Amp#1 runs one side/pair, Amp#2 runs the other pair, run both amps together you run all 4 speakers.

It's an idea to put to the "amp guru's"...

[Sekhmet]

^would really like to know if i can do that cause thats what i'm looking atm atm.

[Searcher]

Thanks for the replies, again!  I don't really want a hotplate and I'm not sure how to run the thing in stereo, since it only has one input.  I guess I can do some of my own research, eh?