per http://support.tixati.com/settings%20-%20transfers%20-%20trackers

Multi-tracker announce mode

   This controls how transfers with multiple tracker groups are announced. The original BitTorrent multi-tracker specification calls for stopping on the first working group, but some users may prefer to announce to all tracker groups at the same time. This is generally unnecessary because PEX peer exchange will provide access to the full swarm so long as at least one peer connection is made.

As is, there are 2 options, announce to "First working group" or announce to "All groups"

I would assume hitting just the first working group is a kinder option. However, as noted this might not be effective unless PEX is enabled.

If I am understanding this correctly, would a 3rd option be helpful?
So as to make it conditional based on either the users setting at Settings/Transfers/General/Miscellaneous/PEX Peer Exchange or whether or not PEX is allowed on the torrent.

"First working group IF PEX is allowed" on both user client and the torrent settings. If PEX is inactive on either, then announce to more than just the First working group, either to more groups or all groups.