How compute the average distance between two distinct motifs insidse a list of DNA sequence?

I've got a new issue...

I would like to compute the average distance between two distinct motifs in the same sequences list than before. Have you some clue on how manage this ???

I just come to do it for one motif like that :

source("motifOccurrence.R")

motif <- c("T", "C", "A", "A")

motidist <- sapply(df, FUN=function(df, motif) {

computeDistance(coordMotif(df, motif))

}, motif = motif)

This R code give me the average distance between a define motif inside all the sequences of my list. And I would like to do the same but with two motif... Can someone help me ?