Yes, there is a way. If I can find it I'll link you the place I got mine but basically the bit that surrounds the very end of the barrel unscrews (you may well need some pliers to get it out) usually on a 14mm CW thread. Then youneed a +14mm to -14mm threaded adaptor that screws in and then leaves the -14mm threaded bit sticking out for you to attach suppressors/tracers etc.
One of these: http://www.ebay.co.uk/itm/SD-14mm-Barrel-Adapter-for-Marui-MP5K-PDW-CW-to-CCW-14mm-to-14mm-/271669997316
also available from Redwolf, Patrolbase and many others.