🚀 go-pugleaf

I am not sure why you are using ITableSuite within your ASB/CSB code, when ITableSuite is already a selection suite interface.
If you want to call ITableSuite::CanMergeCells and MergeCells, you can simply query for ITableSuite using ISelectionUtils, and call those methods from anywhere (e.g. Action Component).

InterfacePtr<ITableSuite>tableSuite((ITableSuite*)Utils<ISelectionUtils>()->QuerySuite(ITableSuite::kDefaultIID));
if (tableSuite->CanMergeCells())
  tableSuite->MergeCells();

If there is a need for you to implement your own ASB/CSB, then you can query for ITableTarget to get the cells that are currently selected, and process a command. (But since ITableSuite already has CanMergeCells and MergeCells methods, it still seems unclear why you would need to wrap those calls in your own ASB/CSB)

Refer to the Selection technote for details.