Options with a o-ringed block

I have an o-ringed block and just ordered a new hamilton head. What are my options here. I wanted to get my head fire ringed but with my block already o ringed I dont think It's possible. Should I just leave the head flat and run it or can I o-ring the head too? Is there any way I can run fire rings with the o ringed block?

You can have the fire rings cut in place of the o-ring in the block. I prefer the fire rings be cut into the block personally. I've seen engines have an oring in the head and block and it worked fine in a puller