You live in an ecosystem where your members might ask a question in your community or on a dozen or more other channels.
It makes far more sense to connect and support that ecosystem than fight it.
The Microsoft Azure community (below) is a great example.
Encourage your members to ask and answer questions on different platforms.
Automatically complete the tags for them to ask questions on each platform.
Assign badges and offer congratulations for members who answer questions on any platform which suits them.
You get far more value from supporting and integrating with your ecosystem than fighting against it. Consider designing a similar homepage for your community.