Most people thinking about applying for a new Amex Card when still holding another one do it for purposes of:
+ a colour change either to a higher colour with a higher annual fee but more service
+ keep the MR account alive when not using Amex much and therefore changing to the less expensive card with full service (in most markets some cobranding cards respectively the green one).
+ grab a decent offer with a welcome bonus in form of free MR points.
So I don't see any sense in opening four or five new credit cards and then cancelling them after two or three months.
IMHO it may be a warning signal for the credit card issuer that you would like to increase the available credit line without asking for it. This *may* trigger a Financial review with the obligation to send in some info like the tax statement.
So I am not able to help here at the moment. Please clarify what the purpose of this transaction should be?
