TomTom Rider 400 linked to Aux input on bike instead of going to bluetooth helmet

I have an issue i dont seem to be able to resolve. Basically when instructions come through to the helmet, it cuts off the intercom, once the instruction has been given, the helmet says intercom connecting, this takes maybe 10-15 seconds to do. An average turn instruction is given 2 or 3 times for each corner. This means the intercom goes off loads of times making it inoperable. I have asked for help on this matter before. At the moment i have to disable all voice commands which means relying on the screen, this also means constantly watching the screen for turn which quite often i miss. I used to have a garmin zumo, i prefer tomtom screens which is why i got this one, however the zumo had a 3,5mm jack output, i ride a goldwing which has a 3.5mm aux input, ideal, this means the headsets can be used for intercom and the speakers on the bike can be used for direction instructions. you could even put in a SD card and listen to music as well which muted automatically when turn instructions were given. But as i say i went for a tomtom device as i simply prefer their screen.

So i got to thinking of ways around this and thought about a bluetooth receiver, i bought one, while it pairs up with the phone it wont pair up with the tomtom rider. So i did a bit more research and i found out that the bluetooth device had to be A2DP. So i bought another one and guess what that does not pair up to the tom tom 400 either. The two units bought were not that much money so worth a try but am i doing something wrong with these units.

I would like to hear off anyone who has managed to solve this issue. Previously someone stated that instructions should not cut off the intercom rather than just mute it. The helmet is a viper rs171 which i think is bluetooth 3. I keep thinking there should be an easy way to do this but am failing on each turn.