First you need to tell us what you mean by spur-thighed.
1) Some people mean the tortoise also known as a Greek tortoise and by the Latin name of Testudo graeca. They are closely related to Hermann's tortoise (Testudo hermanni) and roughly the same size and I'm guessing *might* be able to live together, but I'm sure somebody like EJ could give you a better idea. There are also several types (subspecies) of Greek tortoises, and the Golden Greeks may not mix well with other species. Again, EJ would be a good source of info.
2) Then there's the other tortoise that some people call spurred tortoise or spur-thighed or the Sulcata: Geochelone sulcata. Very different animal. Grows large (over 24" and maybe 100 pounds) and aggressive and not a good mate at all for a Greek or Hermann's.
So let us know which it is. If you aren't sure look up Testudo graeca and Geochelone sulcata on Google images and tell us what you've got. Or post an image.