Can a company participate in two different UTES in the same tender?
A UTE, so that we understand each other, is basically when several companies decide to get together (as if they were the Avengers, but in office version) to fight for a public contract that, honestly, would be impossible for one. It is typical in giant works or projects that require an entire army of skills and resources.
Now, about the million dollar question: can a company be in two different UTES for the same tender? Well look, this depends a lot on the legislation of each site, but in most cases (and in Spain safe) the answer is a resounding "Nope." More than anything because if you leave companies to present themselves in duplicate, the marimorena is armed: conflicts of interest everywhere and the fair competition goes to the garete.
In Spain, for example, the famous public sector contract law (LCSP, for friends) makes it very clear: a company cannot present more than one offer to the same contest, neither alone nor disguised in different UTES. The law explains it in a serious and formal plan, but what comes to say is that if you have control of several companies, you can not cheat yourself several times on different sides. Nothing to play two bands.
If you get caught by skipping this rule, prepare for the drama: sanctions, disqualification, and probably a good legal colleja. So eye, that riding UTES is great to add forces and have more ballots to win, but you have to go with lead feet and not skip the rules. If you have doubts, the most sensible thing is to ask someone who knows the legal issue, because as you get, the joke can be expensive.
So, in summary: utes yes, but with a head. Do not go ready trying everywhere at the same time, that the law is not dumb.