I have want to have rows /columns of certain cell value which changes sequentially. However the number within the cell value that changes is not at the end. Hence dragging the cells does not fill the series.
e.g. 100-LT-1-009-CS1. The next few values in the series are. 100-LT-2-009-CS1, 100-LT-3-009-CS1, 100-LT-4-009-CS1.

The value after LT in the above example is changing. However when I drag after putting the first value it changes to _____CS2, _____CS3, _______CS4 etc.

How should I go about this?