Can we send our research paper to two IEEE conference simultaneously, and then after acceptance, decide which conference proceedings to publish it in?
It is considered unethical in the academic community to submit a paper for simultaneous review at multiple venues (unless it is explicitly permitted by the publications, and you disclose this on submission).
The IEEE guidelines on multiple submission prohibit multiple simultaneous submissions:
Authors should only submit original work that has neither appeared elsewhere for publication, nor which was under review for another refereed publication.
The guidelines further specify that failure to disclose, on submission, that the work is under review for another publication, can result in (after multiple offenses)
suspension of publication privileges in all IEEE Publications for 1 year and rejection and return of all papers by the author(s) that are currently in review or in any IEEE publication's queue (papers may be re-submitted after suspension term has expired).
In addition, engaging in this practice can irreparably damage your reputation in the academic community.
Short answer is yes, but it is unethical. Even when you read the agreement before submitting your paper it appears that the work should be original, that means that it should have not been submitted to other conference or journal. You must put in the shoes of the reviewers, in one hand you make them waste time by reviewing one paper that is already being checked up in another conference. Also you are getting one available spot that could be filled by another research paper by another person.
One advice, take your work in academia more seriously than just submitting like if its a game.
IEEE allows certain authors to submit and publish work that is currently under review.
IEEE likewise allows certain authors to submit and publish work that was previously published.
IEEE likewise allows certain authors to submit and publish work that was published by other persons.
Numerous examples can be found by searching the web.