Two heads connected to one cab

[shadowcat]

Hi, I think 've got a quite unique situation... and I cannot wrap my head around it.

My band now moved into a rehearsal room with another band who are good friends of us.
We want to share our ENGL cabs with each other, so that each band can use fullstacks for the guitars.

So we have four heads but only two fullstacks and the question is: Can we connect the cables in a way that we don't have to always switch cables before practice?

Obviously the ENGL cabs have two input jacks and a stereo/mono switch.
Could we connect two heads to one cab and leave the switch to mono, so that all 4 speakers work for the head which is switched on?
Only one head would be switched on at a time always... but would the other head take damage while still being connected to the other jack?

I hope I made the question clear, haha.

Of course it wouldn't be THAT much of a hassle to just connect the amp that is used before each practice session, but if there's another way...

Thanks in advance!

[Slik_Karl]

You can but the switch on the cab has to stay in the Stereo position,1 head per two speakers in the cab. If you try mono your gonna see flames!!

[markD]

just change the cables. that is your safest bet.

[shadowcat]

Thanks for the answers!
That's what I was worried about, because I know you can put two cabs in a chain when it's switched to mono... so it's pretty logical that there would be current flowing to the unused head when cabled that way.

So, cable switching it is!

[Spivonious]

You can do it as long as the cabs are set to stereo, but then you lose your full stack and just get two 2x12s instead.