Your built-in receivers all use different "languages" to interpret the signals they receive via radio. There is no transmitter that "speaks" RT (Canon/Yongnuo RT), EL (Elinchrom), and X1 (Godox). In fact, there's no transmitter that even "speaks" two of the three. They're all separate protocols. Expecting one transmitter to transmit in all three protocols at the same time would be like expecting a person to speak in one language and be understood simultaneously by three different people: one who speaks only English, one who speaks only Hungarian, and one who speaks only Mandarin.

The best you're going to be able to do is choose one of the three systems for your transmitter to directly communicate with the flash(es) using that same protocol. You would then use add-on receivers that use that same system connected to the other flashes via hot shoe/hot foot or PC connectors. You'll only have E-TTL, HSS, remote zoom/power control capability, etc. with either the RT or Godox flash(es) if you select one of those protocols as your transmitter. The others will only receive a signal to "fire" and all settings will need to be made directly via each flash's control panel.

You may want to note that right now, Godox stands above the rest as they offer a single triggering protocol (X1) that covers their manual-only speedlights, TTL speedlights, bare bulb flashes (manual or TTL), and studio strobes (manual or TTL).¹ Also note that though the transmitters come in Nikon/Canon/Sony/etc. "flavors" because the pins must line up with the pin patterns on the camera's hot shoe, Godox receivers in many of their flashes can auto-switch between Nikon/Canon/Sony/etc. versions of the Godox X1 transmitter. Godox receivers with a hot shoe that attach to the hot foot of a TTl flash are similarly limited by the pin pattern, but they can all manually "fire" anything with a PC port via the PC connection on the receiver. The Godox protocols are also used by several other "branding labels" of gear made by Godox. The most notable is Adorama's Flashpoint nameplate that is made by Godox and is fully cross compatible with Godox gear. There are others, both in the U.S, and in other countries.

The Canon RT system only covers Canon RT speedlights and their third party clones. The Elinchrom system is limited to Elinchrom strobes, all of which seem to be studio monolights. Different Elinchrom "flavors" may or may not be compatible with each other.

Also note that flashes, transmitters, and receivers that use one of Yongnuo's other protocols (YN560/RF605/RF603 and YN622) are not compatible with Yongnuo's RT clones. Yongnuo's RT clones do work with Canon's RT devices and should work with other third party RT devices since they're all reverse engineered to be compatible with Canon's RT devices, although there are some reports that this is not always the case with other third party RT clones.

¹ Godox did use a couple of earlier protocols before rolling out the 2.4 GHz X1 system several years ago. They used other lower frequency radio bands, though, so it's easier to tell them apart. If it is not 2.4 GHz, it's not X1 compatible.