So how do you counter this?

Recently in a game (it's been at least a week), the entire enemy team did the whole & build. They might not have even built Banner and I'm remembering it wrong, but they at least all had Zz'Rot Portal.

By the time they all had we figured out what was going on but it seemed too late to actually counter it. As far as I know, the main way to counter this is to also build .

Just wondering how else you could counter it aside from that. We tried actively looking for the portals and killing them, but when there's 5 the pushing power the enemy team has is just too much to handle for some team comps.

Not saying it's in any way OP but assuming I do run into a team like that again, I'd like to know a way to deal with it.