The answer the question is yes, both can happily co-exist with no problems, however, the red rainbows, assuming you mean Glossolepis incisus (Red Iranian Rainbowfish) cant live in a 90L tank, they require a minimum of 55g (approx 220L) for full growth and swimming space.
If you like rainbowfish, perhaps look at the Praecox (Dwarf Neon) Rainbows, which can live in a 90L, a shoal of 6 - 8 in there with the rosy barbs would be fine.