When you add an account in Mint, every sub-account that is displayed in the provider's website under the set of login credentials you use will be displayed in Mint as well.
If you have two sets of login credentials for one particular provider, you can add the same provider to Mint twice using both sets of credentials.
For example, if you have two Chase accounts, one that belongs to you and another that belongs to your spouse, and each of you has your own set of credentials, then you can add Chase to your Mint account twice.
If one ore more of the sub-accounts overlap (because they are joint accounts), you can choose to hide and/or close one of them. For more information about hiding and closing accounts, please click here.