There are many different examples of stacker door combinations such as centre opening with two doors interlocking to the left and two doors interlocking to the right. There are also examples of three sliding stackers, one active and two non active all sliding two one side. This combination can also be a centre opening, meaning six doors in total and is quite rare. Each individual door or doors in the centre opening situation will have to have their own full length tracks. If they do not exist then they will have to be installed.
Note: Receiving interlocks must be present on the fixed glass panels; these serve two purposes. Firstly to locate the door precisely in the locked position and secondly to lock the doors together.