Headsets that support multiple connections

I have a SE P900 and sync with my PC over BT. I also have a Jabra BT200
headset. The headset works fine when Bluetooth is disabled between PC and
P900, but when PC to P900 Bluetooth is active/enabled the Jabra can't be
used to dial out/receive calls.

Is this a limitation of the Jabra BT200 or the P900. SE say it's the Jabra??

Thanks

Clive