mergePed(x, y, ...)

# Creating a trio where each parent have first cousin parents.
# (Alternatively, this could be built using many calls to addParents().)

# Paternal family
x = cousinPed(1, child = TRUE)
x = addSon(x, 9)

# Maternal family
y = cousinPed(1, child = TRUE)
y = relabel(y, c(101:108, 10))
y = swapSex(y, 10)

# Joining x and y at the common individuals (in this case: `10`)
z = mergePed(x, y)

# Plot all three pedigrees
opar = par(mfrow = c(1, 3))
plot(x); plot(y); plot(z, col = list(red = labels(y)))

# Reset graphical parameters
par(opar)