To load more than one DLL with the same function names, you can temporarily load the functions from the DLL with other REXX names. This can be done using RxFuncAdd. The REXX name is the first parameter of RxFuncAdd.
Example:
/* load the function */ call rxFuncAdd "MyCls",, "REXXUtil",, "SysCls" /* use the function */ call MyCls
(see RxFuncDrop for another example of using this technique; see RxFuncAdd for a restriction)