One wallet with two address.
Name one 'Main' and the other one 'POS Savings' or 'POS for Spending'
Setup 'Savings' and uses your 'POS Savings' address to send POS into.
Use coin control to choose the 'POS Savings' when spending your coins

To turn on coin control from the menu selection choose 'Settings -> Options' Change to the 'display' tab. Click on the box that says 'Display Coin Control Feature'
Then when you go to send you will see a button called 'inputs' Click on 'inputs' and a screen will show all of you coins and the address they belong to. Choose the coins from the address that you want to send from.