How to denote  script in P2SH transaction?
Short Answer
Yes, but there's more than one.
Long Answer
Bitcoin scripts are a stack-based language. The 'separators' are the Bitcoin push-data-onto-stack instructions. There are multiple instructions to push data onto the stack:

OP_0, OP_1, OP_2, ...
0x01-0x75 (Yes, that's their real name)
Push opcode bytes onto the stack
This is most common - the average piece of data in Bitcoin is shorter than 75 bytes.
PUSHDATA1 - Read 1 byte, convert to int, read that many bytes
PUSHDATA2 - Read 2 bytes, convert to int, read that many bytes
PUSHDATA4 ...
OP_1NEGATE - Pushes -1 onto the stack. Somewhat use-impaired.

There's a useful rule of thumb here, though it's not always correct. Take the first byte. Convert it to a number. Count that many bytes forward. That's a single piece of data. Repeat.
Let's work through an example. Let's find the elements of the input script for this transaction.

0100000001cce488677848b7a962f01a525d7cd78139a5be1ab75ead5b7336ba6f512d0388010000008b483045022100b65463abe3b5f79dbe9556180e60db4b6b3a6db7c43132e1e396e73023b34d2402206a412868470f8b83dc266a364b79e0a2acd0f5642181f7d0212c7ea608271a4a0141040ab8f88b419c62dba59d2e685bd3bc07367236d841abf3068b5886cd7a6c7297e721d42a41cb1bbd69ed684cc5d5c738d611d886c4493280b26637abad5603a5ffffffff0280f0fa02000000001976a914f593d5cfb3b74ac2988815cdf26c0420981385b788ac50d2a019000000001976a9148a0c13d08a36e68aa5294ca7e6f06a9946c3f1d588ac00000000

Break it up, find the input script:

version: 01000000
inputs: 01
hash: cce488677848b7a962f01a525d7cd78139a5be1ab75ead5b7336ba6f512d0388
vout: 01000000
input script len: 8b
input script: 483045022100b65463abe3b5f79dbe9556180e60db4b6b3a6db7c43132e1e396e73023b34d2402206a412868470f8b83dc266a364b79e0a2acd0f5642181f7d0212c7ea608271a4a0141040ab8f88b419c62dba59d2e685bd3bc07367236d841abf3068b5886cd7a6c7297e721d42a41cb1bbd69ed684cc5d5c738d611d886c4493280b26637abad5603a5
seq: ffffffff
outputs: 02
amount: 80f0fa0200000000
output script len: 19
output script: 76a914f593d5cfb3b74ac2988815cdf26c0420981385b788ac
amount: 50d2a01900000000
output script len: 19
output script: 76a9148a0c13d08a36e68aa5294ca7e6f06a9946c3f1d588ac
lock_time: 00000000

Now, we know the first piece of data is 0x48 (72) bytes long.

48...3045022100b65463abe3b5f79dbe9556180e60db4b6b3a6db7c43132e1e396e73023b34d2402206a412868470f8b83dc266a364b79e0a2acd0f5642181f7d0212c7ea608271a4a01...41040ab8f88b419c62dba59d2e685bd3bc07367236d841abf3068b5886cd7a6c7297e721d42a41cb1bbd69ed684cc5d5c738d611d886c4493280b26637abad5603a5

The second part is 0x41 (65) bytes long:

48...3045022100b65463abe3b5f79dbe9556180e60db4b6b3a6db7c43132e1e396e73023b34d2402206a412868470f8b83dc266a364b79e0a2acd0f5642181f7d0212c7ea608271a4a01...41...040ab8f88b419c62dba59d2e685bd3bc07367236d841abf3068b5886cd7a6c7297e721d42a41cb1bbd69ed684cc5d5c738d611d886c4493280b26637abad5603a5...