The answer to your question is dependent upon the version of IE that is installed on your system. IE7 and later versions allow for multiple home pages within the same window by utilizing multiple tabs which you can toggle back and forth to.
To create Multiple Home Pages in IE 7 or IE8:
Tabbed browsing must be selected to create multiple home pages in these versions. If it is not turned on, got to Tools/Internet Options and select Settings in the "Tabs" section. You will then choose the options that you would like to be enabled by clicking in the box to the left of those desired.
With tabbed browsing enabled, open IE and navigate to the page you need. Click on the arrow next to the home tab and select Add or Change Home Page. Select Add this web-page to your home page tabs. Repeat this step to add additional home-pages as desired, but be aware that each page added will slow the browser down when it is opened.
IE6 or earlier workaround uses two separate IE browser windows as compared to one window, but you will still be able to toggle between the two and have easy access to each. Officially, only one is the "home page":
Create two shortcuts on your desktop, one for each of the pages that you need to open or set your browser to the page used most often and create one desktop shortcut for the second page you need. Once you have the desktop shortcuts, you can drag them to the quick launch bar for easy access to both (If your Quick Launch is not displaying next to the Start button, right click on the task-bar and check "Show Quick Launch" prior to moving the desktop shortcuts.
If you are unfamiliar with creating shortcuts on the desktop, right-click on a blank area of the desktop and select New, and then Shortcut from the drop-down list. The wizard will walk you through the rest of the steps. It is advisable to have the URL address of the web pages copied into a notepad file so you can easily transfer them into the wizard.
If you want for both pages to open when you start-up your system, open Windows Explorer by right-clicking on Start (using the right mouse button) and then left-click on Explore. Windows Explorer will open to a folder labeled Start Menu with the Programs folder below it. Click on the + sign to the left of Programs, and then click on Startup. If the shortcuts created above are in the Quick Start bar to the right of your Start button, or on the desktop, you can either copy them or drag them into the Startup folder and with this, they will automatically load when you start up your computer.
Another option on almost any browser is to set the second page that you want to go to as a "favorite." Once logged into your home page, you should be able to click on the favorite and go to the second log-in page that you need.