How can we write multiple parsers to use the same lexer?

Looking at class org.antlr.v4.gui.TestRig method process() starting at line 123 I noticed that Lexer classname has to be the same as parser classname.
line 125: ```String lexerName = grammarName+"Lexer";```
How is it possible to use multiple different parsers to use the same lexer?

Start in org.antlr.v4.gui.TestRig.process() around line 123 and inspect how line 125 derives the lexer class name from the grammar name. Trace the TestRig entry point and related argument handling to determine whether multiple parser grammars can share one lexer; done means establishing and documenting a supported way to do so, or clearly identifying the limitation.

Written by the indexing model from the issue text.