I did this on Sewer Bat on the first wave with four enemies since they are just basic thugs.
I wait until one charges you then:
Counter, Strike, Evade over an enemy, Stun nearest enemy, Quick Triple Batarang, Ground Takedown, Strike, Throw, Strike until you can use the takedown, Combo Takedown, Batclaw, Strikes.
It's far easier to do this with four enemies as that is the minimum I've found you can do this in without having to constantly be countering charging enemies or worry about being hit while doing a Ground Takedown. You can easily manipulate enemies to where you need them. Obviously you have to get through all the moves quickly with only four enemies to work with, but it's a fair trade-off for not being overwhelmed and frustrated.