If your American Express cards are issued in the USA this is correct, there is no published feature to permit transfers between cardholders. There is anecdotal evidence that customer service will do this, by telephone, on an exception basis. There is no assurance they will grant any particular request.
What type of cards do you have? Previously, you mentioned that they a credit cards, which suggests Blue from American Express. Is that correct? What would be the benefit of combining the points?
Yes, USA issued and one card is a Blue Amex. The purpose of combining the MR is because since I don't use that card too often I don't have enough MR to redeem for anything worthwhile...less than 2500