How to create a pool of Apache HttpClients with different SSL client authentication certificates

I've been digging through the Apache documentation and other examples trying to create a client that uses Apache HttpClient to call various RESTful web services. (Each web service may require a different client certificate for authentication). Initially, I created a static block of code that initializes HttpClient (with SSLContext information and pooled connection manager):

private static CloseableHttpClient _client;
static {
  HttpClientBuilder clientBuilder = HttpClients.custom();
  SSLContextBuilder sslContextBuilder = SSLContexts.custom();
  sslContextBuilder.loadTrustMaterial(new TrustSelfSignedStrategy());
  sslContextBuilder.loadKeyMaterial(new File("clientcert.p12"), password, password, (aliases, socket) -> aliases.keySet().iterator().next());

  SSLContext sslContext = sslContextBuilder.build();
  HostnameVerifier allowAllHosts = new NoopHostnameVerifier();
  SSLConnectionSocketFactory connectionFactory = new SSLConnectionSocketFactory(sslContext, allowAllHosts);
  clientBuilder.setSSLSocketFactory(connectionFactory);

  RegistryBuilder<ConnectionSocketFactory> regBuilder = RegistryBuilder.<ConnectionSocketFactory>create();
  regBuilder.register("https", connectionFactory);
  regBuilder.register("http", new PlainConnectionSocketFactory());
  Registry<ConnectionSocketFactory> socketFactoryRegistry = regBuilder.build();

  PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
  clientBuilder.setConnectionManager(connectionManager);
  _client = clientBuilder.build();
}

At this point, I can perform requests with the client, and client authentication works fine as long as the server is configured to allow access to clientcert.p12.

What I need is to be able to dynamically change the client certificate for each request based on the value of the required client certificate.

Can a static HttpClient be reused when changing client certificates dynamically? Also, if possible, would I still see a performance benefit of using a pooled connection manager?