...
To create an alias for use at the $Server level for register 5176 which is "Mass" for the Modbus Omni Protocol, the Alias Name would be entered as ‘ModbusOmniDevice.Mass’ (including the device name), and the corresponding item name would be entered as ‘ModbusOmniDevice.5176’ (also including the device name). Server level alias groups are created on the Aliasing tab of the $Server object.
An alias group can also be created for use with a single device or can be created for a group of devices of the same protocol if the tags are the same.
...
See General Object Configuration page.
Alias Records
Activate Tags
The Activate Tags checkbox allows group tags to activate internally without waiting for a client to connect and activate them. Selecting this option will enable ACM to poll all the items in the Alias group without the items being in an OPC Client.
...