Catholics and Muslims also have the veneration of Mary in common I do believe.
All it would take to bring those two groups into high tea together would be a couple of Mary apparitions..say, over Damascus, or hovering over the “well” in I’m-a-nut-job’ Iran. You know, just appealing for prayer for peace and unity and rosary indulgences. No big deal. Just coming together for world peace and unity...and the anti-christ smiles and polishes his shoes..getting ready for that big day..