I have a system of three differential equations with three unknowns, say f(t), g(t) and h(t).

My problem is that the system involves also f(invh(g(t))), g(invh(g(t))) and f(invg(h(t))), where invh is the inverse of h and invg is the inverse of g.

How can I instruct Maple to deal with these inverse functions?