No you cant give two password for protecting or unprotecting the sheet. Instead just have a hidden password which the users won't know and try to code like this...
In the below mypassword is the original sheet password and User1 and User5 is the masking password which you can give it to the users. Use an If statement to verify the masking password and assign the right password to unprotect the worksheet. So that the Users wont know the real password.
Use a text box on form to enter the password because you can mask the password text with a * when users type the password by giving * in PasswordChar property 
Dim sEnteredPwD As String
sEnteredPwD = InputBox("Enter Your Password to Proceed", "Enter Password")
If sEnteredPwD = "User1" Or sEnteredPwD = "User5" Then sEnteredPwD = "mypassword"
ActiveSheet.Unprotect sEnteredPwD
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