[jhgb]

Since you're talking about a "satellite train", so as to speak, I'm not sure you need to "speed up to intercept". If for example the orbital period is 90 minutes and the time between two consecutive satellites passing through the same point is 5 minutes, just make sure that your orbital period at the time of intercept is 95 minutes and then you can shoot down one satellite per orbital period. There's not a lot of maneuvering that the electrically propelled satellites could do on quick notice.