I think of maroon as a reddish purple, or blueish deep red. Experiment with mixing the blues that you have into the different reds you have, adding a small quantity at a time. Different blue/red combinations will give different results, so make notes of what you mixed with what and see what you get.
You may find you just can't get a saturated enough result to satisfy you, in which case you should consider buying a maroon as a separate color. I think PV19 (pigment violet 19) is a nice single-pigment maroon color.