Doubleclick for Publishers (DFP) - Point same size creatives to unique ad-unit

Question

I am having trouble solving this puzzle:

In DFP I have two slots that can receive, one left and another right with the same size, currently, when I program this line item, it's pointed to three different ad-units:

Slot1 - 720x90 Slot_Left - 100x600 Slot_Right - 100x600

Problem is that when I upload the left and right creatives I cannot select where they will appear, and so, when the ads are shown, sometimes the one that should be on the left side is on the right, and the one that should be on the right is shown on the left.

Is there any way to fix this?

Thanks in advance!

Answer 1

I use to solve it (always with Sponsorship line items), setting up as different Line Items; one for the left side and other one for the right.