Your not nuts. Give it a try. I did it in C.FL a few(?) years ago using Don Jaun. Had them planted 18" apart on a trellis on the open end of our car port. In 2 yrs it was a HUGE mass of rose bush covered in deep velvet red.

I've done likewise, planting Austins in complementary colors to grow together--extends the bloom time and is very pretty. Just be sure there is enough amended soil at the bottom for everybody to spread out roots in.

Oh yes, absolutely, I have roses grouped all over the property. One of the pleasures for me is planning the combinations of colors, blooms, and shapes the cultivars will attain when they're mature.

Many are placed to merge as freestanding hedges bordering beds, or to grow up trees together, such as Reve d'Or and The Bishop. I've also paired roses on arbors and tripods: Climbing Maman Cochet with Summer Wine, Viking Queen with Honorine de Brabant, Harlekin + Parade + Mme. Gregoire Staechelin +Aloha, etc. Hybrid musks are grouped in partially shaded areas, such Darlow's Enigma + Marjorie Fair + Nur Majal next to a patio so we can enjoy the fragrance.

So go for it.