Can we submit our research paper for review at two IEEE conferences simultaneously? Can we send our research paper to two IEEE conference simultaneously, and then after acceptance, decide which conference proceedings to publish it in?
No.

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.