VisibilityConstraints - Multiple Item Selection

[R-Jones-99]

Hi all i am using the ProvideUIContextRuleAttribute along with VisibilityConstraints to make sure my Button only appears for .cs files, this works perfectly for single select, however is it possible to allow it to work with multi select too, e.g. I select 3 items in my solution explorer, i would like to only show the button if all selected items end with the .cs extension

Here is my Package class and the VSCT table for reference.

[PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
[ProvideMenuResource("Menus.ctmenu", 1)]
[Guid(PackageConstants.EXTENSION_STRING)]
[ProvideUIContextRule(PackageConstants.COMMAND_VISIBILITY_STRING,
    name: "C# Files",
    expression: "CSharp",
    termNames: ["CSharp"],
    termValues: ["HierSingleSelectionName:.cs$"])]
public sealed class CompanyCodeGeneratorPackage : ToolkitPackage
{
    protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress) => await this.RegisterCommandsAsync();
}

<Commands package="CompanyCodeGenerator">
	<Groups>
		<Group guid="CompanyCodeGenerator" id="CompanyMenuGroup" priority="0x0600">
			<Parent guid="CompanyCodeGenerator" id="IDM_VS_CTXT_ITEMNODE"/>
		</Group>
	</Groups>

	<Buttons>
		<Button guid="CompanyCodeGenerator" id="CodeGeneratorCommand" priority="0x0100" type="Button">
			<Parent guid="CompanyCodeGenerator" id="CompanyMenuGroup" />
			<CommandFlag>DynamicVisibility</CommandFlag>
			<Strings>
				<ButtonText>Company Code Generation (EF)</ButtonText>
				<CanonicalName>.CompanyCodeGenerator.CodeGeneratorCommand</CanonicalName>
			</Strings>
		</Button>
	</Buttons>
</Commands>

<VisibilityConstraints>
	<VisibilityItem guid="CompanyCodeGenerator" id="CodeGeneratorCommand" context="CommandVisibility"/>
</VisibilityConstraints>

I have tried using IDM_VS_CTXT_XPROJ_MULTIITEM however this does not work. Is this pattern supported with VisibilityConstraints and ProvideUIContextRule? I do not see any option for HierMultiSelectionName

Thanks