Quick Question

You would not need to adjust anything on your bass (unless you wanted to).

 

What tuning are they in? How many strings are on your bass?

 

All you really need to know are the chords they are playing. You don't NEED to do anything to your bass, you already have all the notes you need

 

This is not a setup question , but rather EQ (and so probably better suited to 'Live Sound'...)

In the inimitable words of Willie Keeler: "Hit 'em where they ain't..."

If the guitars insist on playing down in the traditional bass part of the spectrum, (why?) you'll need to find another place in the mix to be heard. If they want to go tromping over your territory, you'll probably have to stake out a position in their abandoned upper-mids part of the spectrum. This might be a good application for a 6-string or a 5-string tuned EADGC.

If they don't want you to play there, and they refuse to stay out of your place (IOW - they don't want you to be heard...) they are telling you they don't need you. I expect it'll be mutual right after that. Unless there's a ton of money involved, in which case you can pantomime basslines all night long and have a great time...

 

Actually, it is ... at least that's what the OP says.