Character value can display automatically

Dear Experts,

i have a question for character value.

In BW, we have master data for PH1-PH6.

And if you know the PH6, there is unique value for PH1-PH5.

For example, if PH6 = 111111, PH1 = 1, PH2 = 11, PH3 = 111,etc.

This value is unique.

Now we have a excel layout for user to key in.

User only key in PH6, we want that the value for Ph1-Ph5 can fill-in automatically.

Just like user key in ph6 = 111111, ph1 = 1, ph2 = 11, ect.

I think characteritic relationship can achieve this requirment.

But question is that we must use the exit type for this requriment, am I right.

Can we use attribute or reference data or hierarchy ,etc to achieve this target?

If we use exit, we must create a function to support this requirement.

Thanks and best regards

Alex yang