Hello Daniel,
Not sure to fully understand your issue.
The ‘safest’ approach would be to export your multitrack recording into a single multichannel file (containing 8 channels or more). This can be played back with sfplay~ or spat5.sfplay~ or others. You are guaranteed that all channels will be perfectly synced.
The Panoramix-Ircam patcher (or standalone application) contains a built-in spat5.sfplay~ which can read up to 128-channel files. (see “input player (128)” in the patcher)
Alternatively, you can load several audio files into several players (sfplay~ or spat5.sfplay~ or others) and send them simultaneously a “play” message. With spat5.sfplay~ (and maybe others too?), the playback will actually start at the beginning of the next audio block, so in theory, all the players shall be perfectly synced.
Hope this helps,
T.