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docs/reference/radio/set-group.md

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+# Set Group
+
+Sets the group id for ``radio`` communications. A micro:bit can only listen to one group ID at any time.
+
+Unless specified, the group id is automatically inferred from the script source. Every script with the same exact source code with start with the same group id.
+
+## Important Security Consideration
+
+The functions in the ``radio`` namespace allow the BBC micro:bit to communicate with other micro:bits.
+
+This API does not contain any form of encryption, authentication or authorization. It's purpose is solely for use as a teaching aid to demonstrate how simple communications operates, and to provide a sandpit through which learning can take place.
+
+For serious applications, BLE should be considered a substantially more secure alternative.
+
+```sig
+radio.setGroup(1)
+```
+
+### Parameters
+
+* ``id`` -- a [number](/microbit/number) between ``0`` and ``255``.
+
+### Example
+
+Sets the group to 128.
+
+```blocks
+radio.setGroup(128)
+```
+
+### See also
+
+[receive number](/microbit/radio/receive-number), [send number](/microbit/radio/send-number), [on data received](/microbit/radio/on-data-received)
+