Maybe you can do it, but with plans for long term changes.
Are your tanks stable? What do you have in your tank? Lots of anemones all over? Small frag plugs all over? Anemones and corals don't get along together. Clownfish live 20+ years so you want to be sure you are staying in this hobby long term to care for them before making a commitment to lots more fish.
Clowns are very aggressive, it is how they determine sex and reproduction. It might be cute for a while, but long term I suspect you'll encounter problems. HOWEVER, if you have a plan for rehoming some down the road, it does give you better odds that they'll pair up into breeding pairs... but then they may clean areas of your tank so severely that if you have small corals they will rub the corals to death as they force corals to host them. If you have just FOWLR with rocks and caves, they'll find and make little territories and claim those for egg laying.
Once they start laying eggs, it takes a lot out of them and quality frequent foods are needed. I've found a lot of work goes into trying to keep water parameters stable and coral quality so mixed reef while possible is not the right choice for everyone.
Think hard on this decision before moving forward.