Two girls in the same room with a guy and his buddy is easy in almost any club.  Almost any girl and her 'friend' would jump at the chance.

But be very careful and make sure you know what you are getting.  Do you want the girls to interact with each other?  Ask.  Do you want to swap girls while in the room?  Ask first.  It may cost double of what you expect it to cost.

A few girls may also offer a DP with you and a friend.  Again ask or ask someone there what girl might be available for that.  But again, it might cost double the normal rate, or more.

Otoh, you may be more interested in a partytreff, like Mettmann.  Some clubs have special GB days where such action is not only the norm, but expected.  Sesernechen in Duisburg will certainly meet your requirements, but you will have to be tolerant of other guys there enjoying the same ladies.