How can I to use three directories in the parameter wallet_location in the file sqlnet.ora?

I have in my client three directories with two archives cwallet.sso and ewallet.pk12 in diferents paths for connects to three databases. Each server has the certificates cwallet.sso and ewallet.pk12 and these are imports in the Oracle Wallet. The connections Only validate the first  directory. 

In the client i have the file sqlnet.ora:

SQLNET.AUTHENTICATION_SERVICES= (NTS, BEQ, TCP, TCPS)

SSL_CLIENT_AUTHENTICATION = TRUE

SSL_VERSION = 1.2

WALLET_LOCATION =

  (SOURCE =

    (METHOD = FILE)

    (METHOD_DATA =

     (DIRECTORY = \app\client\product\12.1.0\wallet_desa1)

     (DIRECTORY = \app\client\product\12.1.0\wallet_desa2)

     (DIRECTORY = \app\client\product\12.1.0\wallet_prod)

    )

  )

SSL_CIPHER_SUITES=(SSL_RSA_WITH_AES_256_GCM_SHA384,SSL_RSA_WITH_AES_256_CBC_SHA)