How to share a vlan interface with a bridge and a trunk port?!

Look at bridge VLAN filtering:

https://wiki.mikrotik.com/wiki/Manual:Interface/Bridge#Bridge_VLAN_Filtering
http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1

It uses bridge to connect vlans on different ports and allows to set where they should be tagged or untagged.