This was a series; I seem to remember reading it no later than the early/mid ’90s. An important plot point was a set of nonhumans - blue, I think - that operated in a group mind to understand the ecology of a world. They could decide whether it was safe to colonize the world, and could assist a colony set up on such a world to know exactly what was safe to eat, to do, where were good places to locate the colony, and so on. There was a fair amount of mysticism attached to it, and somehow a human woman became part of one of these group minds.