Salary received by employee from two or more employer in FY2019-20

Employee has to disclose total salary received from all the employers

In so far as tax return is concerned you have to declare salary received from every Employer.

but you do have a right not to disclose your salary income from previous employer to your new employer.

Section 192(2) gives you an option to disclose the salary from previous employer for calculating TDS to be deducted. It's just an option and not obligation..

It's okay if you don't disclose the salary received from the previous employer, but your concern is that you need to combine two salaries and check if you have tax liability, or advance tax payable at your end... if yes, pay it accordingly and save yourself from interest on deferment/late payments..