Make it a 4 piece band and let the harp players exchange some licks........
Or.........
Just tell your friend to fuck-off cause as a harp player he makes a good butt-fuck and you don't wanna' see him in the vicinity. Then when Harp 2 turns you down for another picker because you suck and as a picker you make a good butt-fuck and he don't wanna' see you in the vicinity, you can go groveling back to Harp 1 who will happily kick you in the balls.