SEM BCS - Two Sided Elimination

Hi,

I want to use "Two sided elimination" for elimination AP/AR.

In method for interunit elimination=> tab selection, there are selection1 and selection2.

The question is :

Do i have to put item AP/AR in selection1 and AP/AR in selection2 , or... i have only put AR in selection1 and only AP in selection2?

Please advise.

Thanks in advance.