This is going to be a bit messy, but I think that it may be possible with events structured as follows:
city=any of the target cities
denominator= (1=100%, 2=50%, 3=33% etc probability of getting tech)
technology=any of the technologies you want given to the Franks.
This is pretty simplistic - any tech can be received from any city - but may result in the Franks not getting some techs.
If you want to make sure that the Franks receive all the "Civilized I" techs you will need to arrange it so that taking cities A or B will produce only tech X, taking cities C or D will produce only tech Y etc..
Trying to keep track of which techs have been received and which ones have not is not a place I would want to go.
BTW, could you please post the number of target cities, the number of "Civilized I" techs and the number of special techs. Some cities may need 2 events, one for a "Civilized I" tech and one for a special tech.
I assume that this is not a multiple event file scen.