3speed, Use a gear inch calculator and plug in both your combination and your riding partner's combination. It's possible that similar ratios can be found using a shifting scheme employing both derailleurs.
Perhaps another cassette will help. I swapped my mountain bike's 8S 11-30 to an 11-28 to enable a single shift to a middle ratio I liked. I'm using that 11-30 cassette on my primary touring bike and due to tire circumference and outer chain ring size differences, it works quite well. I can also cannibalize the 11-28 if I wish to.
I must admit that I'm willing to walk up a climb, or coast down a descent to fill in my more often used GIs. My touring bike's GI range is 19.8" to 108.0", FWIW.
Brad