Is it possible to connect one non-MIDI keyboard's sounds to another?

Greetings,

I am very grateful for the help received so far.

I am curious if it is possible to connect or play one keyboards sounds to another keyboard.
Let's take two toy keyboards for example. The circuits are so simple, that the answer must
be yes. Are there any variations here? Also, what if I wanted to take a toy keyboard and
hook it's sounds up to a larger inexpensive keyboard? I'm not talking about MIDI. These
toy keyboards would have pitch resistors which could be replaced with pots. I am thinking
that one could take the lines that go to the toy keyboard's keyboard and wire them into the
place where the larger keyboard's keyboard connects to its sound producing circuits.