AutoMount USB Devices

[Lyrax]

Hello together,

maybe I am stupid, but I can't find a solution.
Host: iMac
Guest: Win7
Virtualbox: new Version + extension Pack

So, I've added 2 USB Devices to the Virtual box. Started it. Plugged them in. They were recognized. Everythings fine.
I reboot, the 2 Devices are not in the Guest System. I have to unplug them and them plug them in again.

My Mac always grabs the Devices, when I Quit VB. After starting the Guest system, the Mac does not unmount/eject. Any way to solve this?
I do not want to have 4 Device to plug them in every time I start the Guest VM.

Thanks for the help in Advance!
Lyrax