get https://app.bitgo.com/api/v2//wallet//transfer/
A transfer is a wallet specific object. Each transfer will only output the respective wallet id which the transfer is associated with.
If there is a transaction between two BitGo wallets, then two transfers will be created, one for wallet A, and one for wallet B. Transfer A will only annotate the walletId on entries where the address belongs to wallet A. Transfer B will only annotate the walletId on entries where the address belongs to wallet B.