BHG Missions vs. Corsairs

[Wilf_Brim]

Hello to everybody especially fellow Bounty Hunters,
I recently got back to game and start earning some money doing missions for my guild. My problem now is that those Corsair's cap ships Osiris class are pretty much tougher than they used to be so I am here for an advice, how do you deal with them? Do you have any special tactics against them?
I am cooperationg with some BHG friends, we have destroyer and two GBs but enemy is often in group of 4-6 BS and we have no chance against them.
One more thing, can someone pls tell me what type of shield is most effective against them?

Thx very much for any advice, WB.