It is currently not possible to filter on the "Customer account", "Name" or the "Description" field within the group assignments ("TAMRebateGroupLink").

The filter function would be especially useful for the rebate maintenance because if the group consists of many customers or suppliers the maintenance effort is more difficult. If a customer or more consists of a group with a lot of members (e.g. 500 or more), the whole assignment list must be laboriously searched or searched via the Excel AddIn per workaround. 

Here the filterability of the fields would be absolutely necessary for the end user from our point of view.