We have created two campaigns and added the leads to them.

However, it is possible that some of the same leads will be in both campaigns. I don't want those leads to be contacted twice.

Is there anyway to use Campaigns to filter leads?

I tried a custom view but this does not work.

We could do it with a custom field but this is a manual process so likely to fail. 

Does anyone have any ideas on how to automate this please?