Constrained k-means algorithms in R (must-link constraints)
For the given problem I would apply constrained Hierarchical clustering in R. That is more efficient in this case. If you like to apply Hierarchical clustering the package is "rioja" and the function that you can use is chclust().
This is not constrained K-means implementation in R but this should solve your actual problem.

There are two types of constrained in chclust() function, you can set those with the help of method parameter in function. This will add the constraint on the basis of sum of square.You can read in detail about these constraint with simple search.

This chclust function will produce the constraint object and you can check the proper number of group by using other functions in "rioja" package.

A practical implementation of same can be checked on below link:
https://gist.github.com/benmarwick/7097120