# Multiple Containers

With the multi-container support process, you can add multiple containers to a single resource with one call, when invoking CICS resources using containers.

The process puts multiple containers into the CICS channel, which is then passed to the program. This allows greater flexibility in program design and use. Container Process in the CICS panel indicates how the different input message types and container features are handled.

To use multiple containers, perform the following steps:

1. In the Container Process field in the CICS panel (`SXTP05I`), specify M for the message derived type.
2. When configuring the input message type, consider the following points:
   - Do not specify an input conversion rule.
   - EMS properties cannot be used as data value replacements because they are only used for directing a recipe service process such as `tibss-BES` or `tibss-resource`.
   - EMS Bytes messages, Text messages and Stream messages are passed as User Data to one input container. Bytes and Stream types are handled as binary data (OPA). Text type is handled as string.
   - For EMS Map and Rendezvous Messages, each message field is a separate container with the container name being the same as the field name supplied in the message. The type of data in the container is based on the message field type.
3. When configuring the output message type, consider the following points:
   - Do not specify an output conversion rule.
   - EMS properties cannot be populated with user data. However, they can be added in the Recipe properties panel with constant or system data such as `tibss-envelope`, `tibss-ss-id`, `tibss-cfg-id`, and so on.
   - For EMS Bytes, Text and Stream messages, if one container is received from BES, a message is created using all the data from that single output container. If multiple output containers are received, a Substation ES error is generated. No data response message is created.
   - For EMS Map or Rendezvous messages, when one or more output containers exists, each container becomes an opaque field type in the message with a name that matches the container name.
4. During CICS execution, consider these points:
   - Multiple input containers can be created. One or more output containers are allowed, depending on the output message type.
   - The only Reply Methods that are supported are 0 (none) and 1 (status). For a Container Invocation of `T` (transaction), there is no reply message with data.

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