Employees that are already working in a company are called 'existing employees'.
They can also be called current employees.
Those have been recently recruited are called - .'new employees' or 'new recruits'
I hope that helps!
すでに会社で働いている社員のことを、existing employees と呼びます。
current employees と呼ぶこともできます。
最近雇われた社員のことは、 new employees や new recruits と呼ばれます。
参考になればうれしいです！
アメリカでは、new and oldという形容詞で対比します。
old employees=「既存社員」
new employees=「新入社員」（中途採用の含む）
あなたが言うように、new と oldの間には、コミュニケーションの難しさがあります。
アメリカでも日本でも、事情は同じです。
ここまでお読み頂きまして、ありがとうございます。
感謝
"Senior Employees!"
"Senior staff members"
"Senior colleagues"
"Senior" does not just imply age, it also means that they have been with the company a long time and it also speaks to the knowledge of that person.
I'm an existing employee.
MEANING= I already work here or have worked here for quite a while.
I am a current employee of this company
MEANING= this is the same as the first phrase and means ‘you already work at this company’
I am presently an employee here
MEANING= this is a more formal way of saying you already work here.
You could also say:
‘I’ve worked here for ___x amount__ years’ – more formal
‘I’ve worked here for quite a while’ – informal
‘Yeh I’ve worked here for ages now!’
I'm an existing employee.
意味：私はここですでに働いていて、しばらくの間働いています。
I am a current employee of this company.
意味：これは１つ目の言い方と同じですが、「あたながこの会社ですでに働いていること」を意味します。
I am presently an employee here.
意味：これはあなたがすでにここで働いていることを言う、フォーマルな言い方です。
When you join a new company, you may find things difficult at first - especially adopting new systems and routines and integrating with the existing labour force. If you are lucky some 'old hands' may take it upon themselves to show you the ropes and introduce you to some of the seasoned workers there.
To show someone the ropes = to assist and help someone learn new procedures or ways of working.
新しい会社へ入社すると、まず最初に色々な事が大変なように感じるかもしれません。
-特に新しいシステムや決められた方法など既存社員の人々と溶け込むことなど。
もしあなたがラッキーならいくらかの 'old hands'（ベテラン）さんがやり方を教えてくれたり、そこにいる "seasoned workers"（熟練社員）へ紹介してくれるかもしれません。
To show someone the ropes = やり方やコツを教えてくれたり、手伝ってくれる事を意味します。
Current employees will have a better paid pension scheme than any new employees
Current: Happening now /existing at this time. In this example current employees will have some advantage over all those who join the company now...
(IE new employees!)
Current employees will have a better paid pension scheme than any new employees
Current：今起きている／今存在している
例文では、既存の社員は今入社する人よりも優遇されている、と伝えています。
Current employees will have a better paid pension scheme than any new employees
〔訳〕既存の社員は今入社する人よりも年金がいい。
We would most likely refer to older employees as the, "current," or, "existing," employees as these are the people who have been in the company for awhile. We can also refer to them as, "senior employee's," because they have been there longer and have seniority in how the business works.
イギリス 
日本 
南アフリカ 
アメリカ合衆国 
