Septic Question - Garage Apartment and Future House on Same Plot

We just bought a piece of property and are wanting to build a garage with small living quarters (think 1bd, 1bt, tiny kitchen) to have/live in for a few years while we save up to build the actual house on the property. We are concerned with how this will work with the septic. Will we be able to put in the septic for this garage/apartment and later on, build the house and tap into the septic? The house will not be attached to the garage/apartment structure. Has anybody been through this or know if/how this would work?

The land is perc'd for 4 bedroom septic, and we would put in the 1000 gal septic initially, so the # of bedrooms and septic size isn't the issue (the future house wouldn't be more than 3 bedrooms). I am wondering if we would be required to have a second septic tank for the second structure (which I'm sure wouldn't work with the plot/septic fields). We don't want to do the garage/apartment if it will inhibit the main house later on.