Non-Doctrinal Counter for Urban Cancer?

Recentlly I struggled alot against Urban Soviets 3v3 - not only because of my own lack of skill, but also because of constant pressure of enemy's on my teammates.
Got 4 games - 2 in 2v2, and 2 in 3v3. Both times in 2v2 we got ourselves locked in spawn area - mostly because squad of engies and Maxim rushed closest to our spawn brickhouse, then turning it into FOB or whatever this abomination name is, while his teammate harrasing our squads in the field.
If first time we somehow managed to pull it tru(mostly because of "teamwork" andy my flamenwerhfer 251), second time it was pure cancer - his teammate called in 120-mm mortar, efficently countering every one of our mortar teams.

In 3v3 it was a little bit different - mostly because when i spotted these puny little flags, I called for help, so we focused it with 2 mortar and 2 leigs - brought it down in seconds.

So my question is - is there any NON-DOCTRINAL methods to prevent/counter FOB-spam? I mean, flametruck is cool and all, but she is rather weak and need some time to get these cheesy flames into work, while 45-mm AT-cannon acts like bloody Bofors, turning into full-auto mode while close to FOB.

I want to try 50-kg bombdrop or some sort of static arty, but they both unlocks only at 5 and 9 CP while FOB can be spammed from very beginning.
Artillery officer proved to be efficient counter strat with it vet1 heavy mortar barrage if dropped on top of building, but again - it is doctrinal, if I to choose him, it will deny me of my other, preferred commanders.

You want a non-doctrinal answer to a doctrinal ability? Well in that case the best and cheapest option is most likely the flamer ht, or alternatively getting an OKW ally to invest in a stuka which might be a safer option.

If you're open to doctrinal solutions, then dive bomb, lefh18, and mortar ht incendiary barrage comes to mind.

The soviet forward observation post can indded be extremely powerfull in team games on certain maps, so these options are probably your best bet.

Recommend the mortar HT flame shell ability, a couple will burn it down, with not much risk to your units as it can just pull back once fired.

If you see they have the commander, rush critical buildings early, before capping.

You could also ignore it and double up on the other opponent, but be quick and also have a long term plan for the fob.