source expression transformation after CONCAT

Hello,

Currently, we have a client who is migrating from HFM to FCC, and they used to rely on FDMEE scripts to transform data during the import process

Now, in Data Exchange, we are using the Source/Target Expression functionality.

In the source expression we use CONCAT:

which works; however, we are unable to clean the data properly. This is because this source doesn’t allow adding conditionals, so even when a column is blank ("") or null, it still adds the delimiter. For example:

A99999-- (Double dash)

Is it possible to stack Source expressions in one single dimension or even use conditional ?