Making a custom toolbar for COM tools

I'm building a range of COM tools to use in ArcMap. Two of them are closely related: one of them imports from an ASCII file and the other exports to an ASCII file. What I want to do is bundle the two together on a single toolbar. ie. when the user goes to the customise toolbar option (which is a standard for a variety of applications) and select commands I want to have the two toolbar buttons grouped together so they can drag them together instead of dragging them individually. I'm not sure if this is possible though as I've never seen it done but I've been asked to try.