Difference between 3 way and 4 way give up agreements in Futures Clearing

Hello everyone,

Just wondering if anyone can clarify the difference between a 3 way and a 4 way give-up agreement in the context of futures trading/clearing.

Just to give some context. we are a public fund and one of our external fund managers requires futures trading for interest rate risk management. Our custodian has recommended that we enter into an agreement with a third party clearing broker (who provides futures clearing in required markets) via a 3 way or 4 way so that our external managers can access futues clearing.

What is problematic is that some of our other external managers are already trading futures and we have not previously entered into any such agreements. The custodian seems to be unresponsive on why this is happening.

If someone knows kindly shed some light on the workings of futures clearing for external managers via clearing brokers it'll be greatly appreciated