Making custom audience from facebook group members

Hello!

I want to target members of specific facebook groups and who like specific pages. I've found tools that take the names from a group, and then another tool that will match them up with linkedin to take public email addresses to create a custom audience. But it's not very effective - less than 10% of them came up.

Does anyone know a way to do this or have any suggestions?

TIA

this is what I am thinking to do nowadays for my fb arbitrage

It used to work in 2017 .. I think it's too late now to build an audience based on email list.
Best you can do is to invite them, FB has a new option that let you invite members to groups based on an email address.
So instead of being a friend of them to have permission to invite, you can simply invite by email.
I hope it helps.