For the time being, here is a work-around.
• Go to "My campaigns", e.g. by clicking "Back to Roll20" near the top right of any discussion page.
• Click on "view details" under the campaign that you need to deal with.
• Click on "copy/extend campaign"
• Under "copy from this campaign" click to remove the check beside "Players & Player Settings (including Macros)"
• Click "I'm ready, create campaign"
• Then go into the new campaign, copy its player link from the chat pane, and send it to the players you want to keep.
This has problems: the players won't be happy about having to re-build their macros. But it is the best trick I know using the tools we have at the moment.