SQL JOIN QUERY with more than one items in common: Find the franchise pairs that operate together in more than one location

With this R script, I have a table called dfmt that lists the location, revenue and franchise. I want to find the franchise pairs that operate together in more than one location.

set.seed(43)
f<-c(   'hilton',
        'marriot',
        'redroofinn',
        'motel 6',
        'holiday inn',
        'best western',
        'raddison',
        'daysinn',
        'howard Johnson',
        'econolodge')
towns<-c('Camden','Washington','New York',
 'Baltimore','Richmond','Miami','Fort Myers','Austin',
 'Dallas','Houston','Chicago','Cleveland','Rochestor',
 'Pheonix','Tempe','Tampa','Augusta','Atlanta','Boston',
 'Stamford','Denver','Fargo','Jacksonville','Savannah',
 'Charleston','Elon','Raleigh','Greensburgh','Gatlingburg',
 'Morgantown','Wheeling','Pittsburgh','Scranton','Binghamton',
 'Syracuse','Manchester','Portland','San Jose')
mtdset<-
lapply(f,FUN=function(x,ptowns=towns)
{
N<-sample(1:length(ptowns),1)
loc<-sample(ptowns,N,rep=F)
rev<-1000*sample(100:1000,N,rep=F)
#paste(x,loc,rev,sep=',')
dfv<-data.frame(loc=loc,rev=rev)
dfv<-cbind(dfv,fr=x)
})
dfmt<-mtdset((1))
for(x in 2:length(mtdset)){
 dfmt<-rbind(dfmt,mtdset((x)))
 }
dim(dfmt)
head(dfmt)
tail(dfmt)

So far, I have a query that finds the franchise pairs that operate in the same location:

select T1.fr, T2.fr2 from dfmt T1 join (select fr as fr2, loc as 
loc2 from dfmt) as T2 on T1.fr < T2.fr2 and T1.loc = T2.loc2 order by loc;

I do not know how to go from here to find the franchise pairs that operate together in only more than one location.