Agglomerating OTUs by taxonomic rank

Hi!

I recently started learning mothur and I am testing its functionality using an OTU dataset that I exported from Bioconductor mia (here are some examples).

I am currently looking for a function in mothur to agglomerate (sum) OTUs by a specific taxonomic rank (e.g., Family) and return the agglomerated counts table (similar to mia::agglomerateByRank). I spotted the make.shared, tax.summary and classify.otu as potential candidates, but I do not have a list file. What I have is a OTU-level count table, taxonomy, tree and sample metadata.

Could you give me a hint how agglomeration could be done in mothur?

Thanks in advance!

P.S. An example dataset I am using is attached to this issue in GitHub.