The problem I see is the difference in water requirements - peonies require minimal water, roses considerably more. Peony and/or rose experts might have different ideas as to whether or not this is a good pairing.

I did have peonies and roses in the same bed. They grew fine and seemed compatible with each other. I moved the peonies into their own bed because to me they were not an attractive combination. Neither roses or peonies require any fertilizer or spraying here and are largely pest free, so it was only they did not look good together in my opinion. Al

If I was mixing the two plants I would either use climbers at the back or group one type of plant at each end and the other in the middle. My preference is for the roses in the middle so you can place other plants at their roots.

If you have a peony grower in your area or can travel to one please look at the foliage along with the flower. You will have the foliage to look at longer than the flower. Some of the foliages can look really interesting. The ones with macrophyllia have hugh leaves. But there are many different types out there.