Hey, welcome to the gog forums. I don't think you will see a complete pack on gog as they only sell games at either $5.99 or $9.99 at the moment, three of the tex murphy games already cost $9.99 so I don't see it being possible unless they change how they price things. It's possible that they will do a promo one weekend where you can save a few dollars on each of the games but no way of telling if or when that would happen.
I would just advise buying them one at a time in order and if a promo pops up before you have them all you can save a bit of money on the rest.

I asked my very dear friend Yamada, who owns a Credit Card, and he'll buy the Tex Murphy games for me! Yiiipee!
He's the best ;)

For a while, the titles were selling very well. I don't think a sale will happen soon.

Well I bought Killing Moon for nostalgia purposes, but I'm not buying any more until there's a complete pack. I'm not interested in messing about with individual discounts, I want to buy them all together or not at all.

But you can! Just use "add to cart".
All Tex Murphy games are available here on GOG.

It is multilanguages?
If yes what languages?
THX ;)

No, only English as far as I know.

I hope they will do Tex Murphy's promo weekend again.

I meant at a discounted price for buying them all at once - not just 5x5.99 or whatever

Doubt that'll happen. They never do that for $9.99 games.