BLF extensions monitoring on a remote server

my Linksys SPA962+SPA932 BLF work fine as far as I monitor extensions on the local Asterisk server (server A), the 962 is logged in with its own lines. The problem is I want to monitor on BLF buttons another server’s extensions as well. Some BLF buttons from server A some from server B.
What I can achive is defining the buttons as speed dial but hints from the other server do not work.
Has anyone suceeded in such a configuration?