I am using KM 1.5 beta2 and this is how that can work in this version.
Go to first homepage. Open a new tab and go to second homepage. Save the session under a name ( maybe homepage ). You can then load the named session whenever you want your homepages. If you want the homepages at startup then go to sessions - options and set the named session to run at startup. You have the option of an automatic run or a question whether to run.