[tor-relays] Hello guys. Is is possible to choose one's Entry Guards?

I didn't realize the TOR Project had their own mailing list server, though it makes sense. I'm studying tor relays, especially obfsproxy, and I thought I'd go ahead and ask a question. If you have a hidden service, and hide that on Server A, then have it connect via obfsproxy to Relay B, can you configure a manually-chosen list of entry guard relays to enter the wider Tor Network from Relay B? [Hidden Server] -- obfsproxy --> [Bridge Relay] -- tor --> [Specific Trusted Entry Guard Relays] -- tor --> [TOR Network] Is this currently possible?