2012 audio / non navigation

[lionsden]

I tried to use usb thumb drive in the trunk without success. I have a 595lm garmin on the bar, of course i need the hollster interface to hear gps in headset. took that male plug from hollster and plugged into my phone that is bluetoothed to the gps. got what was playing on phone and it displayed on gps screen don't know how but all i want is music. only have volume control on hollster box. can i get a female 3.5mm to plug to hollster and two male ends - one to my gps to her talk to me and one to hear music will that work? any suggestions will be appreciated. Thanks