LaTeX multiple equation references in one

Is it possible to combine multiple equation references into one, like it is for the \cite command? What I would like is the following:

\begin{subequations}
 \begin{align}
  a & = b \label{eq1} \\
  c & = d \label{eq2}
 \end{align}
\end{subequations}

Some text referring to the formulas \eqref{eq1,eq2}.

which would then compile as "Some text referring to the formulas (1a,b)." Obviously, this example doesn't work, but I'm hoping there's a package out there that does something similar. Any ideas?