Adding a G/L under an Alternative number

Hello experts,

I have a requirement do create a hierarchy of alternative account and G/L accounts underneath of each alternative account. This alternative acc are selected based on chart of accounts.

There is a set that was created in ECC on SKB1 and Alternative account field.  I created a custom data source on those 2 and loaded data. it shows the alternative accounts as well as the necessary range.

Because the leaf is a G/L, the info Objects to hold the hierarchy was created using G/L template. But the G/L is compounded with a chart of account.

All my node value in the hierarchy I created has not corresponding chart of account in transaction data. so when I run my bex query, everything in my hierarchy is unsigned.

But from the SKB1 table, I can get the GL and the alternative account. Question is : do I have to build my own hierarchy alternative --GL or there is a way  I can just use some abap code in the hierarchy transformation to add the GL underneath the alternative a/c?

Thanks

JB