Hi!
Yes, you can, but for certain project - certain wdt and wdt.
ACE looks the following order for this files:
1. <projname>_wdtitle.wdl (wdt) - where <projname> matches the name of the active project in the same folder as the project WDT file.
2. default_wdtitle.wdl (wdt) - in the same folder as the project WDT file.
3. default_wdtitle.wdl (wdt) - in a folder in the AutoCAD Electrical search sequence.
So you could have <projname>_wdtitle.wdl and default_wdtitle.wdl in the project folder. But ACE will use only <projname> files.