Bluetooth 4.0 Button

I'm having a circuitboard with buttons on it..the positive wire delivers a signal to the button..once the button is manually pressed it connects with the negative wire and sends out the signal..however, when I take this red wire and connect it to my Feather 32u4 board on pin 11 for instance, then run it to the negative its always on..meaning I can't control on or off.. What I Would like is a button which I can control via bluetooth I don't have to manually press this button anymore..rather be able to roam around and press the button on my app on my Android phone to turn it on or off.. So what I have so far is my Feather 32u4 and this other circuitboard with the pushbottons on it and my app on my Android phone..what I need is some kind of hardware to connect the red (signal) wire with the black wire.. Anybody got an idea what I can use to accomplish this taks? Thanks, Nick :confused: