Create an R Script to Generate a Specific Type of Bar Graph

I would like someone to create a R statistics software script, or find an existing R statistics software script, or modify an existing software script which will allow me to create a specific type of very customizable bar graph. Basically, I want to be able to make customizable scientific journal publication quality bar graphs. I want the bar graph to have error bars, sample sizes and other text above the error bars, significance bars showing which bars have statistically significant difference (*, or **, or ***), customizable graph size, customizable labels so that the font and size and rotation can be edited, customizable bar color, customizable bar border width, and customizable axis width. Basically, I want to be able to make a graph which looks as close as possible to the graph in the attached file. This graph was made in Excel. Ideally, I would like the labels from the generated R graph to be editable in Excel, but this is not a requirement. Note that I would like the labels to be able to contain greek letters as well as have part of the label in italics. I would also like to be able to add or remove bars while keeping the width of the overall graph the same. Additionally, the significance bars must have 3 parts: one horizontal straight line going from one bar to the other, and two vertical lines going from each end of the horizontal line down toward the bar below to the next element of the graph (like in the attached picture).