Duplicate headphones control buttons on an adapter
You could buy TRRS male and female (plug and socket) connectors, and wire it to a circuit which connects different resistances to the GND and MIC pins for play (direct short, i.e. 0 ohms), next and previous track (something like 30 ohms off the top of my d but it's probably way different). Measure the resistances across it and you can then build a circuit to do so.

Here is a basic circuit I've thought up which should work. The "something" resistances is what you measure between GND and MIC while pressing the 3 buttons one by one...







simulate this circuit &ndash; Schematic created using CircuitLab