Is it permissible for priests who normally celebrates the Extraordinary Form of the Mass to concelebrate Mass?

**Is it permissible for priests who normally celebrates the Extraordinary Form of the Mass to concelebrate Mass when saying the Mass according to the Tridentine Rite??** What about at some special occasions, such as the blessing of an abbot? It seems fare to say that vast majority of priests who celebrate Mass according to the Tridentine Rite do not concelebrate their Masses with other priests. However, I would like to know, if in fact it is permitted under certain circumstances, either in our actual times or even historically (perhaps in some ancient variations that were employed in historical Latin Usages like the Sarum Rite)? Has Rome ever allowed this particular practice in the Extraordinary Form? - Latin liturgical rites