A Merge Module can be subject to conditional install as part of a larger feature, but you cannot make individual parts of a Merge Module subject to a conditional install. You can, for example, set up a Server install where IBConsole, the Command Line tools and the Documentation Pack are each separately selectable as part of a "custom install", but you cannot select down to the level of "isql.exe" and "gbak.exe". The .msm files supplied here all contain their dependencies. For example, if you select ibserver.msm (appears as "Interbase 6 Server files" in the list presented by Installshield), Installshield automatically selects ibclient.msm, plus the Microsoft redistributables containing msvcrt.dll and mfc42.dll.