Do you mean permanent Deacons?
If that is what you mean, then that is a little more complex. I do know of one FSSP parish which has two permanent Deacons, it is the FSSP parish in Mableton, Georgia.
I believe that what happened, was that the two Deacons were already ordained and were in active ministry at a Novus Ordo parish when the FSSP parish was established, the Deacons then asked for permission from the Bishop and the FSSP to transfer to the FSSP parish and be in ministry there, they were allowed to do so.
With that said, I do not believe the FSSP offer formation for the permanent diaconate.