Attestation form /Relieving

My query is that 1. I joined organization x and intimate the organization x about filling of application for job in Organization y. 2. After selection I resigned from organization X and got relieved on simple redignation. 3. I went to Join Y organization but forgot to submit relieving letter to Y ORGANIZATION. Y organization didnt asked for attestation form and Also not asked about any previous employment but it asked while giving offer of appointment to submit NOC AND RELIEVING REQUEST..I POSSESS RELIEVING FROM X BUT FORGOT TO SUBMIT IN Y.. 4 I joined Y and its been two years and now i applied through proper channel for another Job Z and submit Noc during interview. 5. I got Selected in job Z and submit attestation form mentioning both X AND Y JOBS IN Z. 6. NOW whether Organization Z will go for fresh police verification or medical or it will ask from Y the required police verification report and medical report . 7. If it go for second option i.e Z asked PVR and medical from Y . Then both Z and Y will come to know that i have not submit relieving fromX organizatin while joining Y organization. In that case i will loose both job. 8. Now if the second case happens what should i do?? All X Y and Z are govt organizatiin central;state and state govt jobs respectively Please response experts