SEACR multiple control files

Question

[a_bis]

I would like to peak call some .bedgraph files from a CUT&RUN experiment using SEACR. However there is only space to upload one control file, and I have three IgG replicate files. What is the best way to manipulate these three files to get an "average signal" IgG file that I can then make into .bedgraph format and use as a control file? Thank you.