So you're Advent being doubled by TECs very close by on both sides.
If you don't get feed, you're bound to lose in a tier 0 battle for your homeworld against the two of them in the long run. And if they're both only two jumps away (maybe an asteroid in between?) that means they'll have fleets on your homeworld ASAP - if they're any good. If you're playing mediocre to semi-OK players, one strategy would be to SB up to protect your labs, frigate factories, and fleet. A starbase will hopefully give you the freedom to then research flak, and then Illuminators, and build up a good number of them - Illuminators in large numbers are almost unparalleled at shredding enemy fleets, regardless of enemy fleet composition. The trick is to not die before you reach that point - and having enough income to support a good number of Illuminators is also a serious problem. Hopefully you were able to get an out-of-the-way roid and a neutral or two. That's the best-case scenario and is still extremely questionable, and is likely to work only against the more noobish opponents.
The biggest threat is from Embargo. If one or both of the enemies attempts a true Sova rush, you'll probably be too crippled to build up enough Illuminators in time. Even if you do get feed, the slower ship building result of Embargo may prove to be too much. And if one enemy uses an Akkan instead, pray that they aren't smart enough to use Targeting Uplink + LRM to destroy your starbase from a safe distance.
If one of your enemies is not smart enough to rush and spam within the first 5 minutes, you have an opening to use tier 0 to fight off the other enemy and to then bring your fleet back in time to fight the other - and you really want to be able to build Illums by then. Without of a substantial advantage of some kind you'll probably die; feed is nearly essential. Building up to 40+ Disciples as quickly as you can may allow you to attack/pursue/destroy enemy capital ships with relative ease, which might result in the enemy retreating their fleet from your HW. It's doubtful but one possible option to consider. Remember that TEC have Ogrovs - you need a decent fleet by the time the enemies realize they can use Ogrovs.
That said, if either of your enemies are halfway decent, they'll both be attacking you very soon and you won't have the freedom to build up enough to survive and will have to evacuate.
A big part of this situation is when to realize that it's hopeless and that you have to relocate. If I were in your situation I would probably just build a Progen/Halcyon and get out of there without using money on defenses or a fleet.
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Oh, and if your allies can't manage to win their side of what would basically be a 4v3, the game is probably over anyway.
