Glad you found these samples useful and yes the issue you are describing is very common in OSGi.
So here is what you can do:
On the publishing side you export service with extra properties that will allow you to uniquely identify it in the future:
And then on the receiving side (as you mentioned) you can filter via filter attribute of service reference:
<osgi:service id="inboundService" ref="inboundChannel"
<entry key="service.name" value="channelA" />
Hope that helps