Sayila - this is not a problem to 'overcome'. This type of activity would be in direct breach of journal copyright procedure. It's not so much that it is unethical - it's enshrined in copyright law. Reputable journals will 'demand' that if they send a manuscript out for review (and especially in they accept it) that it has not been submitted elsewhere. As part of the submission process, these journals will ask you to declare that you understand this before submission. Your academic 'reputation' could be compromised if you make a false claim and journals may be alerted for future submissions.
Sure - you could submit to as many 'predator' journals (as they do not follow copyright laws) as you wish - but that would be a waste of time and money.
Babu- Just Think about the whole work to be followed by editorial board starting from submission of the manuscript, initial checking, reviewer efforts and so on .So if u submit same Article in two journals, clear violation of academic publication ethics.
We should not upload one article to multiple journals simultaneously. It should not be ethical. if uploaded to multiple journals and be published same article in more than one journal and if the journal is not open access then journal authority may blacklisted author's name. Abdenour Kheloufi is correct that Just choose only one journal and send to others a withdrawal letter.